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Author: 


Dowd,  Albert  Atkins 


Title: 


Tools  and  patterns 


Place: 


Date: 


[ 1 922] 


COLUMBIA  UNIVERSITY  LIBRARIES 
PRESERVATION  DIVISION 

BIBLIOGRAPHIC  MICROFORM  TARGET 


ilASTEIl  NEQATIVE  • 


ONQINAL  MATERIAL  AS  FILMED  *  EXISTING  BIBUOQRAPHIC  RECORD 


Dowd,  Albert  AtUns,  1872- 

Tools  and  patterns,  by  Albert  A.  Dowd  "New  Tpr^ 
Industrial  extension  institute  f4018j  t°^^^^3  i  f^^?? 

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Series  title  in  part  also  on  t-p. 


\        Tools..  2.  Machine-tools.  3.  Pattern-making.      i.  Title. 


Library  of  Congress 

Copyright  A  503195 


TJ1180.D7 


18-16995 


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LIBRARY 


School  of  Business 


FACTORY  MANAGEMENT 
COURSE  AND  SERVICE 

A  Stxiea  of  Interlocking  Text  Books  Written  for  the 
liidiistrkl  Exiensioii  Insittate  by  Factory  Man- 
agers and  CkintnlUng  Enj^neers  as  Part 
of  llie  Factory  Management 
Course  and  Service 


INDUSTRIAL  EXTENSION  INSTITUTE 

INCORPORATED 

NEW  YORK 


ADVISOBY  OOUNCIIi 


mmoLMB  Thul  Wwrn,  Pwk.,  Chablbs  P.  Steinmetz, 

nwrnuuMB  ,  cmsulting  Engineer, 

CbaSLBB  E.  Punk,  Secy,,  General  Electric  00. 

GmsL  A.  Btockawat,  Tmbas.,  Jmivis  R.  Harbeck, 

YUte-PreM.  American  Cm  Co, 
*™  "  Vice-Pret.  Strathmore  Paper 

Charles  C.  Goodrich,  Co.,  Lieut.  Oo/.  Ord- 

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WMliAW  W.  mm,  Charles  B.  Going, 

AuMuiaal  Engi-         Formerly  Editor,  The  Engir 
PaWte   sen**  Oornm,  •lllHiW  ftl*WlrW 


BTAFF. 


a  R  Khoeppel, 

OMIMUtiHli  AlfiMi'** 

IfKTEB  BliWMFIELD, 

Oon»uUant  on  PeraonnO. 

H.  A  TwOTOiD, 

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ConmOHmg  MutirM  MmflmMf' 
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Con««I«iiHr  En§lmM^' 

WiLLABD  L.  €AS1, 

Mt.  Wtllard  L.  C<Me  A  t;«i» 

David  Moffat  Mtebs, 

Engineers, 

Joseph  W.  Roe, 

Prof,  Mwhtne  Detign,  Sheffield 
Saentiflo  8ck»^  Y»U  Vniv. 

AUHEBT  A.  DOWD, 

Conmtting  Engtmcer, 

WnxiAM  T.  Himv, 

eMMimif  iiMMwtHai  mmtmm. 

ClBABU»  W.  MoKAT. 


Oboanization  Aim  Abmiwwwia^ 
miir. 

IjABOB  AKD  COMFEISATIOH. 

puomnro  ahd  TiMEp#roiiT. 

PlIMiBAflllfO  Aim  STOBinOk 

I]iii(ii8iitA&  FXHiiaro. 
Executive  StatihiisaIi  C5WJm-Mi» 
Tm  Vagkobt  Bunjniii. 

ICfen  Pown  PiA»T. 

taB  ifMAmoAi.  BQUimm 

Tools  ahd  PATmro. 

Manduno  Maweal  nr  Faoxob- 

ies. 

YAunna  Utoubtbial  Pbopebtmb. 


TOOLS  AND  PATTERNS 


BY 

ALBERT  A.  DOWD 

Member  A,  S,  M,  £, 
CmuuMmg  Eugmeer  ,  SpedaUsmg  in  MmMm  Skop 
PImmmg  md  Tod  Demgnmg 


VOLUME  10 
FACTORY  MANAGEMENT  COUMSE 


WDUSTRIAL  EXTENSION  INSTITUTE 

INCXIRPORATBD 

NEW  YORK 


Ce|iyrigiil,1922;iiy 
fifDUSTRIAL  EXTENSION  mSTITUTE 

niGCWMMUIBI 


PREFACE. 

Many  factoiy  executives  are  chiefly  concerned  with  the 
commercial  end  of  their  business,  and  yet  do  not  possess  the 
technical  training  to  enable  them  to  judge  of  the  relative 
value  of  the  methods  of  production  used  in  their  own  factory. 
In  this  they  are  at  a  decided  disadvantage.  Others,  however, 
do  attempt  to  obtain  a  teehnieal  training  while  engaged  in 
the  management  of  their  plant,  and  profit  largely  thereby. 
A  thorough  training  along  mechanical  lines  may  not  be  neces- 
sary, but  it  is  an  excellent  thing  for  the  executive  to  familiar- 
ize himself  at  least  with  the  f imdamental  principles  under- 
lying meehanieal  work. 

Tool  equipment  needed  to  produce  a  given  piece  of  work 
need  not  be  understood  in  detail,  but  the  executive  i^ould 
know  the  difference  between  a  boring  bar  and  a  milling  cutter, 
for  instance,  and  should  understand  something  of  the  reasons 
why  one  type  of  tool  is  more  suited  to  the  work  in  hand  than 
ano^er.  He  should  also  know  what  reasons  there  are  for 
planing  a  piece  of  work  instead  of  milling  it  ;  or  boring  and 
reaming  instead  of  drilling.  He  should  know  what  dass  of 
work  requires  fitting  of  such  a  character  that  the  surfaces 
must  be  scraped  in  order  to  produce  a  proper  bearing.  He 
should  understand  something  about  the  various  machining 
processes,  and  also  something  about  grinding.  When  a  turn- 
ing operation,  is  indicated  and  when  a  surface  needs  to  be 
ground  to  secure  accuracy  are  all  essential  points  regarding 
which  a  progressive  executive  should  be  posted.  In  addition 
to  these,  the  production  of  interchangeable  work  should  be 
grasped  in  its  fundamentals.  He  should  further  know  the 
possibilities  of  gauging  work  to  produce  it  with  a  minimum 


vi 


PREFACE 


of  expense  and  within  the  required  limits  of  accuracy  con- 
gistent  with  the  commercial  quality  of  the  product.  If  the 
exeeutiTe  does  not  understand  something  of  these  details  he 
muBl  depoid  entirely  mi  Mi  rabordinates  for  information. 

In  mcder  to  aariat  tlie  progreanve  man  and  to  enable  him 
to  aeenre  eoneiae  data  on  tool  equipment  in  a  single  yoliime» 
this  book  has  been  written  and  arranged.  The  intention  of 
this  treatise  has  been  to  take  up  the  points  mentioned  in 
such  a  way  that  a  non-technical  man  ean  readily  grasp  the 
fandania&tal  prinei]»les  underlying  tbe  matters  pertaining  to 
tod  equipment  It  is  the  bdief  of  tiie  author  that  exeeatiires 
win  find  themsdves  yastly  ben^ted  in  their  work  by  a  eare- 
ful  study  of  its  contents;  for  it  is  evident  that  the  man  who 
knows  the  essential  principles  underlying  the  design  and  up- 
keep of  his  tool  equipment  will  be  much  more  likely  to  obtain 
mairimiim  dSei^i^  in  bis  product  than  another  who  is  not 
80  weil  posted. 

AlAERT  A.  DOWD. 


TABLE  OP  CONTiaiT& 


CBAFTEB  I 

.  HAND  AND  FORGED  TOOLS 

PASS 

The  Details  of  Manafactnring   1 

Manufacturing  Conditions   2 

Interchangeable  Manufacture  ........  3 

Tool  Equipment   5 


Classifieation  of  Hand  and  Forged  Tools   7 

Files   8 

Haeksaws   10 

Cold  Chisek   12 

Scrapers   15 

Forged  Tools  ;   19 

Grinding  Tools   24 

Tools  for  Holders    .  *.   25 

CHAPTER  II 

DROP  FORGING  AND  BLANKING  DIES 

Principles  of  Drop  Forging   26 

Dies  for  Drop  Forging  .                                      .  28 

Blanking  Dies     ............  29 

Follow  Dies   30 

Gang  and  Compound  Dies                                  .  31 

Forming  Dies   32 

Sub-Press  Dies   34 

vH 


I 


I 


vm  TABLE  OF  CONTENTS 

CHAPTER  m 

DRILLING,  BOEING,  AND  REAMING 

Drills  .   35 

CJoic  IDjriUs  38 

Countefliorai  .    .  *                                         .  39 

Reamers   41 

Inserted-Blade  Reamers   43 

Taper  Reamers   44 

Boring  Took                                            .    .    ,  46 

FlatrCutter  Bonng  Bars                                    .  48 

Adjustable  Boring  Tool  for  Tool-Boom  Work    ...  48 

Be<»8siiig  Tocdi  .    ,   50 

CKAPTBR  IT 

TURNING,  FORMING,  AND  THREADING 

Hollow  Mills   55 

Turning  Tools   57 

Adjustable  Turning  Tools   ...    i    ....    .  58 

Open-Side  Turning  Tools   60 

Overhead  Turning  Tools     ,   60 

Taming  Tods  for  Vertical  Boring  Mills  .....  62 

Cutting-off  Tools     ............  64 

Threading  Tools   65 

Goose  Neck  Threading  Tool   67 

Forming  Tools    ............  68 

CHAPTEB  y 

MILLING  AND  PLANING 

Milling  Processes   72 

Factors  Influencing  Machine  Seleetiini    .....  73 

Milling  Cutters   ............  75 

Slotting  Cutters  

Angular  and  Special  Gutters   79 


I 


TABLE  OF  CONTENTS  ix 

Gear-Toothed  and  Form  Cutteni  .   81 

Miscellaneous  Cutters   83 

Interlocking  Cutters     .    ,  ,    .    .  86 

Planing  Tools     .   S7 

CiSAFTEB  ¥1 

BROACHING 

The  Purposes  of  Broaching  ,   89 

Preliminary  Treatment  ..........  90 

Broaching  a  Square  Hole   91 

Broaching  a  Round  Hole   92 

Four-way  Keyway  Broaches   94 

Broaches  for  Irregular  Holes   95 

CHAPTER  VII 

SURFACE  AND  CYLINDRICAL  GRINDING 

Grinding  Material  .  97 

Grinding- Wheel  Shapes   99 

Surface  Grinding  Methods   100 

Cylindrical  Grinding     ..........  104 

External  Taper  Work   ..........  106 

External  Form  Grinding   .........  106 

Internal  Grinding    .   107 

Cylinder  Grinding                                            .  108 

€SAfTBE  Tin 

SHOP  EQUIPMENT 

Standard  Equipment   110 

Surface  Plates    .    ...........  Ill 

Straight-edges  and  Parallels   112 

Hand  Vises    .   114 

C-Clamps   116 

V-Blocks   116 

Bench  and  Pipe  Vises  ..........  117 


TABLE  OF  CONTENTS 


CHAPTER  IX 

MACHINE  EQUIPMENT 

Necessity  for  Proper  Tools   US 

Drill  Chucks  and  Sockets   .  120 

Tapping  Attachment  for  Drill  Press  .    .    .    .    .    .  123 

Collets  and  Cliueks  .    .   .    .  125 

St^  drndn   126 

Two^awed  Chudn   127 

Geared  Scroll  Ckiiek   129 

Air-Operated  Chucks   130 

Four-Jawed  Independent  Chuck   132 

MaeMne  and  Manufactoriiig  Vises   134 

Taps,  Dies,  and  Holdera    .........  136 


GBAFTIK  X 

FIXTURES  FOB  PLAIN  AND  STBADDLE  MILLING 


Nature  and  Variety  of  Fixtures   139 

Necessity  for  Proper  Holding   140 

Milling  Fixture  for  a  Connecting  Rod   141 

Straddle  Milling  Fixture  Working  from  a  Finished 

Surface  143' 

Gang  Milling   145 

End  Milling  a  Slotted  Bracket    .......  145 

Fixture  for  Angular  Milling   147 

Fixture  for  Form  Milling   148 

Index  Milling  a  Pair  of  Levers   149 


Index  Milling  Fixture  for  Quantity  Prodnctiffin  ...  150 

FIXTURES  FOE  CONTINUOUS  MILLING 

The  Value  of  Simplicity    '  154 

Continuous  Milling  Fixtures  for  Cylinder    .    .    .    .  156 


TABLE  OF  CONTENTS 


xi 


PAGE 

Fixture  for  Becker Continuous  MiUing  Machine  .  158 
Spline-Milling  Fixture  160 


C3HAPTER  XII 

FACE-PLATE  FIXTURES 

Fixtures  for  Single  Pieces   164 

Fixtures  for  Quantity  Production   166 

Fixtures  for  Cutting  Packing  Rings   ......  166 

Faee-Plate  Fixture  for  a  Hub  Flange    .....  167 

Self-Centering  Fixture  for  a  Bough  Casting  ....  168 

Fixture  for  Thin  Aluminum  Castings   169 

Fixture  for  an  Irregular  Bracket   172 

Counterbalanced  Fixture  for  a  Connecting  Rod  .    .    .  173 

Fixture  with  Adjustable  Counterbalance    ....  175 

Eccentric  Fixture  for  a  Ring  Ppt   177 

Swinging  Eccentric  Fixture  178 

CHAPTER  XIII 

AEBOBS  AND  MANDRELS 

Definition  of  Terms   181 

Arbor  with  Expanding  Shoes   183 

Split  Ring  Expanding  Arbor  ........  184 

Expanding  Arbor  for  Automobile  Flange    ....  186 

Expanding  Arbor  for  an  Adjusting  Nut     ....  188 

Expanding  Arbor  for  a  Bevel  Pinion   189 

Expanding  Pin  Chuck  for  a  Piston   192 

Threaded  and  Knock-off  Arbors   194 

Knock-off  Arbor  for  Threaded  Collars     .....  196 

Special  Arbor  for  an  Eccentric  Packing  Ring ....  198 

CHAPTER  XIV 


GENERATING  AND  FORMING  ATTACHMENTS 

Cknerating  Curved  Surfaces  200 

Simple  Radius  Generating  Attachment   .....  201 


xii 


TABLE  OF  CONTENTS 


PAGB 

BadiQB  Forming  Attiehment  for  Crowning  Pnllesrs  .    .  203 

PIslon  Forming  and  Grooidng  Attaebment  .    .    .    .  206 

Angular  Generating  Cro»^de   208 

Eccentric  Turning  Device  for  Packing  Rings     .    .    .  209 

Bevel  Generating  Attachment  for  a  Turret  Lathe  .  .  211 
Badins  G^ierating  Attachment  for  a  Vertieal  Turret 

f  latlie  214' 
Angnlar  Generating  Attachment  for  Vertical  Turret 

Lathe                                                     .  216 

Internal  Radius  Boring  Attachment   217 


VERTICAL  BORING  MILL  FIXTURES 

Cmistmction  Featnrea  .....    ^  220 

Vertieai  Boring  IfOl  for  Thm  Work   221 

Special  Fixture  with  Tapered  Plug  Locator  ....  22i 
Expanding  Arbor  and  Faceplate  for  Vertical  Boring 

Mill   226 

Vertical  Boring-MiU  Fixture  for  a  FragUe  Aluminum 

Casting  228 

Simple  Fixture  for  Machining  an  Eccentric  ....  231 

Sliding  Fixture  for  Boring  a  Pair  of  Cylinders  .    .    .  233 

Threaded  Knock-off  Arbor  for  Vertical  Boring  Mill  .    ,  235 

CRAPTBR  XVI 

GRINDING  FIXTURES 

Adaptability  of  Cutting  Fixtures  238 

Magnetic  Chucks   .  240 

Orinding  Fixture  for  Uniyersal-Joint  Part  ....  241 

Piston  Grinding  Fixtures   .    .    .  '  243 

Internal  Grinding  Fixtures   244 

Grinding  Fixture  for  Universal  Joint  Member  .    .    .  246 


TABIil  OF  CONTENTS  xUi 

PAGB 

Adaptable  Fixture  for  Grinding  Spur  Gears  ....  248 
Adjustable  Fixture  for  Grinding  a  Bevel  Pinion     ,    .  250 

Grinding  Fixture  for  a  Large  Bevel  Spring  Gear  251 

CKAPTER  XVn 

OPEN  DRILL  JIGS 

Functions  and  Operation   253 

A  Simple  Plate  Jig  .    ,  *    !    ]  256 

Plate  Jig  with  Supplementary  Supporting  Ring         .  258 

DriUJig  for  an  Oil-Pump  Cover   260 

Open  Jig  for  a  Lever  ]  261 

Open  Jig  for  a  Lever  with  Stud  Locator  ....  263 

Open  Jig  for  a  Small  Bracket  264 

Set-on  Jig  for  a  Transmission-case  Cover  .    .    .    .    ]  266 

Set-on  Jig  for  a  Gas-Control  Plate    .    .    /  .*    ]    *  267 

cmFFER  xvm 
CLOSED  JIGS 

Bushing  for  an  OU-Pump  Shaft   270 

Drill  Jig  for  a  Rod-Supporting  Bracket  .    .    .    ]    .  272 

Jig  for  Automobile  Hand  Lever  ]  274 

DriU  Jig  for  a  Bearing  End-Cap                           ]  276 

Drill  Jig  for  an  Eccentric  Bushing  ]  278 

Drill  Jig  for  a  Radius  Brai^et   .......  280 

Orill  Jig  for  a  Crooked  Lever  !    .  283 

Large  Trunnion  Jig  .  '    '  284 

GHAFTEBXIX 

LUBRICATION  OF  CUTTING  TOOLS 

Necessity  of  Lubrication    ........  289 

Composition  of  Cutting  Lubricante  201 


TABLfi  OF  CONTENTS 


PAGE 

Lmbrieatmg  Compofimd  for  Stod  • 

Ooillliig  by  Liibri«8tioii  •    •  ^ 

Lubricating  Stream  to  Remove  Chips   2% 

Lubricating  Through  the  Spindle  of  a  Turret  Lathe     .  296 

Mood  Lubneatioii    .   298 

CHAPTER  XX 

CUTTING  FEEDS  AND  SPEEDS 

A  Careful  Study  Required   301 

Definition  of  Cutting  Speed     ........  301 

Focmnla  for  Determining  Catting  Speeds    ....  302 

Bditaon  of  Speed  to  Feed  ....    ^    ...    .  304 

Conservatiye  Cutting  Speeds   306 

Importance  of  Proper  Speeds  and  Feeds  .....  307 

Allowance  for  Exceptional  Cases   308 

£ffect  of  Lubricant  on  Feed  and  Speed   .....  309 

General  Boles     ....»••..•*•  310 

CHAPTER  ZXI 

PLANNING  AND  LAYING  OUT  WOBK 
TmA  Engineering  Metliodi 

Preliminary  Proeeasei   317 

Prdlminary  Layout  of  Operation  .......  318 

Machine-Tod  Equipment    .   319 

Jigs,  Fixtures,  Tools,  and  Gauges  .......  322 

Laying  Out  Operation  Sheets   323 

Free-Hand  Sketches  .                                 ♦    •    .  330 

If^ilrifig  Layout  Sheets  330 

Time  Study  Sheets  •    •   /  ^ 

Machine  Tools  Reqniped                             .    .    •  384 

Setting  Piece-Work  Prices                              .    .  S8§ 


TABLE  OF  CONTENTS  m 

CHAPTER  XXII 

ESTIMATING  COSTS 

PAGE 

Time  Factor  in  Estimating  Costs  .......  337 

Broad  Experience  Necessary  337 

Usual  Causes  of  Failure   339 

Skilled  and  Unskilled  Labor    .........  340 

No  Hard  and  Fast  Rule   341 

A  Manufacturing  Case   342 

Overiiead  Expense — ^Hourly  Basis   343 

Different  Methods  but  One  Principle   344 

csAPTEs  zxm 

INTERNAL,  EXTERNAL  AND  THREAD  GAUGES 

Accuracy  Required  in  Interchangeable  Manufacture    .  346 

Terminology   347 

Terms  Used  in  Gauging   349 

Setting  Limits  for  Interchangeable  Work     ....  351 

Marking  Limits  on  Drawings   356 

Internal  Limit  Gauges  357 

Internal  Taper  Gauges   359 

Male  Thread  Gauges    ..........  362 

Bxtemal  Gauges   354 

Snap  Gauges  for  Widths  

Templet  Gauges   367 

Ring  Gauges  for  Ciylindrieal  Work    ......  368 

Receiver  Gauges   370 

Taper  Ring  Gauges  .  372 

Master  Taper  Gauge  for  Female  Gauges   373 

Female  Thread  Gauges  ..........  374 


mi  TABLE  OF  CONTENTE 

CHAPTER  XXIV 

PBOFIIiS  AND  INDICATINa  GAUGES 

PAOB 

Gauges  for  High  Accuracy                                     .  376 

Standard  Instrumenta  of  Precisioil    ......  377 

Dial  Indicator   379 

Pralmeli  Moid  Gauge  ..:    1    ......  380 

Mndi-Pm  Gauges   385 

Mush-Pin  Gauge  for  Taper  Shafts   388 

Plush-Pin  Gauge  for  Contours   389 

Mush-Pin  Gauge  for  Indicating  Two  Surfaces  Simul- 

taneoudy   390 

Indicator  Gauge  for  Testing  Alignm^t  of  Connecting- 
Bod  Bearings    391 

Special  Indicating  Gauge  for  an  Automobile  Cam  Shaft  396 

Peeler  Gauge  for  an  Automobile  Crank  Shaft    .    .    .  399 

Electrical  Contact  Gauge  for  Cams   401 

Proile  Inspection  Gauge    .   402 

Coneentridtj  indicating  Gauge  for  Migh  EsqilosiTe 

Shells  *   404 

Johaussott  Gauges  «    i    i    t    ?    •  ^ 

CSAfTIB  TKW 

PATTERNS 

The  Use  of  Patterns  ......    .    .    ^    .    .  407 

Form  of  Pattern   408 

Method  of  Molding   409 

Cores  and  Core  Boxes    .    .    .    .    .    .    .    .    ,  ,411 

Two-Part  Pattern  and  Method  of  Molding  .    .    .    .  414 

Circular  Cover  Pattern                              .    .    .  416 

Pattern  Bequiring  a  Three-Part  Flask    .....  417 

Other  Forms  of  Patterns   418 

Tools  for  Pattern  Making  ......    .    .    .  419 


TABLE  OF  CONTENTS  xm 

OHAFTBR  ZZYI 

RATTEEN  RECORDS  AND  STORAGE 

PAGE 

Desirability  of  Pattern  Records     •    ,    .    .        .    .  421 

Quality  of  Patterns                             .    ]        [    [  422 

Economy  in  Combination  Patterns    .......  424 

Gear  Molding  Machines  ..........  425 

Pattern  Record  Cards   ....    .    .    .    ]        ]  425 

Marking  the  Patterns   426 

Storing  the  Patterns  ^    [  427 

CHAFTER  XXVII 

CARE  AND  STORAGE  OF  CRUCIBLES 

Clay  Crucibles   429 

Graphite  Crucibles   430 

Storafee  of  Crucibles   432 


TOOLS  AND  PATTERNS 


CHAPTBB  I 
HAND  AND  FORGED  TOOLS 

The  Details  of  Manufacturing.— Any  machine  tool 
in  itself  is  of  little  practical  use  unless  f urijished  with 
suitable  cutting  tools.  So  also  any  factory  is  incom- 
plete unless  the  shop  equipment  is  efficient  and  the 
methods  of  handling  the  work  are  in  accord  with  the 
most  modern  practice.  The  manufacturer  who  neg- 
lects these  vital  points  and  overlooks  the  many  de- 
tails connected  with  his  work,  or  who  is  satisfied 
with  antiquated  methods  and  equipment  will  eventu- 
ally find  himself  distanced  in  the  race  of  progress  by 
his  more  up-to-date  competitors.  Recent  develop- 
meHiP  in  tool  equipment  and  modern  methods  of 
handling  are  so  far  in  advance  of  older  methods  of 
treatment  that  it  is  imperative  for  a  successful  manu- 
facturer to  study  the  details  of  his  equipment  more 
carefully,  so  that  his  own  judgment  will  enable  him 
to  stop  the  leaks  which  may  be  responsible  for  losses 
in  produetifm  and  to  apply  new  princip|||||||rhich  will 
bring  his  efficiency  up  to  the  maximum. 

The  purpose  of  this  book,  then,  is  so  to  instruct 
the  progressive  executive  in  the  various  details  upon 
which  his  success  depends  that  he  may  be  able  to 

JL 


2 


TOOLS  AND  PATTERNS 


judge  intelligently  of  his  shop  equipment,  to  develop 
Us  methods  of  handling  idong  the  most  approved 
mechanical  lines,  and  to  control  economically  his  en- 
tire organization.  In  order  to  treat  so  extensive  a 
subject  logically,  it  will  be  necessary  to  separate  it 
into  several  broad  divisions,  each  of  which  may  be 
again  divided  as  seems  desirable. 

Manufacturing  Conditions.— In  any  factory  the 
methods  of  handling  work  and  the  equipment  most 
suitable  for  particular  eases  are  largely  dependent 
upon  the  jsroduct  that  is  to  be  manufactured.  The 
quantity  produced  is  a  very  important  factor,  for  it 
is  obvious  that  methods  can  be  developed  to  produce 
interchangeable  work  m  a  large  scale  when  there  is 
little  likelihood  of  a  change  in  design,  and  yet  these 
same  methods  might  not  prove  economical  where  the 
production  was  small  and  when  there  is  a  strong 

■bility  of.  a  change  in  design  from  time  to  time. 
Ids  of  handling,  tool  equipment,  special  ma- 
chines, and  many  other  details  must  be  planned  in 
accordance  with  the  work  to  be  done.  Now  while  the 
small  manufacturer  can  not  bring  into  use  the  many 
labor  saving  devices  of  the  big  producer,  he  can 
nevertheless  profit  by  the  other  man's  experience 
and  can  develop  similar  processes,  frequently,  suit- 
able to  his  own  work  but  on  a  smaller  scale.  It  is 
therefore  of  the  highest  importance  that  he  should 
become  familiar  with  the  best  methods  of  manufac- 
ture as  they  have  been  developed  by  progressive 
people,  and  that  he  should  study  the  application  of 
principles  to  determine  how  far  they  may  be  applied 
to  his  own  work. 


HAND  Am  FOEGED  TOOLS 


3 


Many  instances  are  seen  where  a  small  manufac- 
turer runs  along  **in  the  same  old  ruf  year  after 
year  and  even  makes  a  comfortable  income  for  a 
time,  until  at  last  his  dwindling  profits  show  him  that 
something  is  radically  wrong  and  that  he  must  look 
into  some  of  the  details  of  manufacture  more  closely 
or  be  content  with  a  much  smaller  profit  than 
formerly.  Evidently  a  condition  of  this  kind  does  not 
develop  at  once;  it  is  a  gradual  process  and  there- 
fore is  much  harder  to  combat.  When  such  a  con- 
dition first  becomes  apparent,  a  course  of  treatment 
is  necessary  in  order  to  prevent  further  losses.  In 
actual  practice,  though,  it  is  difficult  for  a  manufac- 
turer to  realize  that  he  is  losing  ground,  because  it 
seems  to  him  that  he  is  continuing  along  the  same 
lines  that  he  has  followed  with  success  for  a  number 
of  years. 

This  state  of  affairs  may  be  likened  to  a  slow  pro-' 
cess  of  decay  or  a  lingering  disease  which  becomes 
chronic  after  a  considerable  period  of  time.  The  best 
of  all  remedies  for  a  disease  of  this  kind  is  knowl- 
edge. As  the  manufacturing  world  progresses,  and 
as  new  methods  are  developed  and  applied,  the  execu- 
tive must  keep  pace  with  his  competitors  and  profit 
by  their  experience  as  far  as  possible. 

Interchangeable  Manufacture.— Strictly  speaking 
the  process  of  interchangeable  manufacture  is  applic- 
able only  to  high  production  work  when  a  great 
number  of  parts  of  the  same  kind  are  to  be  manu- 
factured. When  parts  are  truly  interchangeable  any 
one  part  can  be  used  in  the  place  of  another  without 
the  necessity  for  hand  fitting.  In  an  automobile,  for 


4 


TOOM  AND  FAVrnmB 


example^  a  broken  part  can  be  replaced  with  a  new 
one  with  the  assurance  that  the  new  part  will  fit  as 
well  as  the  old.  Theoretically  an  entire  machine  can 
be  built  by  the  interchangeable  system  in  such  a  way 
that  all  the  parts  can  be  assmbled  to  make  a  per- 
fect whole  without  the  need  of  any  fitting.  Practic- 
ally, however,  there  may  be  a  few  parts  that  must  be 
''touched  up'*  with  a  file  here  or  there,  or  there  may 
be  a  hole  drilled  at  assembly  in  order  to  complete  the 
mechanism.  But  it  is  an  accepted  fact  that  by  the 
greatest  care  in  manufacturing  and  by  a  proper  sys- 
tem of  ganging  and  inspection,  hand  fitting  and  ma- 
chinh^  operations  at  the  &ne  of  assembling  can  be 
done  away  with  entirely. 

When  any  product  is  to  be  mannfketnied  on  the 
interchangeable  system,  the  ganging  of  the  various 
components  and  the  system  of  inspection  are  of 
supreme  importance.  The  various  parts  which  go  to- 
make  up  the  completed  product  must  be  mannfae- 
tured  in  snch  a  way  that  there  will  be  no  more 
variation  in  size  than  the  nature  of  the  mechanism 
will  permit,  and  this  variation  must  be  held  within 
carefully  fixed  limits.  For  this  purpose  gauges  must 
be  made  snch  that  fhqr  can  not  be  applied  to  the 
work  if  the  variation  is  too  great 

By  means  of  limit  plug  gauges  for  the  inspection 
of  holes  and  limit  snap  gauges  for  outside  diW|#ons 
any  number  of  male  paces  can  be  made  to^HHl^ 
sponding  female  pieces  in  flie  desired  manner. 
Shoulder  distances,  flanges,  contours  of  irregular 
parts,  and  many  other  kinds  of  fits  can  be  held  within 
the  desired  limits  of  aeemracy  by  a  proper  system  of 


MAMB  AND  FOBGED  TOOLS 


gauging.  The  matter  of  allowances  for  fits  of  vari- 
ous kinds  must  be  most  carefully  worked  out  accord- 
ing to  the  nature  of  the  product  to  be  manufactured. 
Thus,  the  allowances  made  for  running  fits  in  a  piece 
of  farming  machinery  would  be  much  greater  than 
in  a  high-grade  automobile,  and  yet  the  parts  would 
be  interchangeable  in  the  one  case  as  well  as  in  the 
other. 

Tod  Equipment— The  tool  equipment  for  any  fac- 
tory may  be  divided  into  two  broad  groups,  perish- 
able tools  and  permanent  tools.  For  purposes  con- 
nected with  cost  finding  these  groups  iMMII^ 
by  a  more  or  less  flexible  line,  but  from  the  mechani- 
cal standpoint  this  grouping  is  by  no  means  specific 
enough  and  can  not,  therefore,  be  followed  out  logi- 
cally without  causing  more  or  less  confusion.  For 
example,  it  is  evident  that  files  or  hacksaws  are 
perishable  tools,  because  they  wear  out  in  use  and 
can  only  be  replaced  by  new  ones  as  they  cannot  be 
re-sharpened.  On  the  other  hand,  jigs  and  fixtures, 
surface  plates,  and  other  tools  of  like  character  may 
be  classed  as  permanent  tools  because  their  lives  are 
very  long  and  they  can  be  maintained  and  put  in 
good  condition  at  a  nominal  cost,  unless  of  course 
they  are  accidentally  broken.  As  this  book  deals  with 
the  mechanical  aspect  of  the  tool  situation  rather 
than  the  cost  finding  end  of  it,  I  shall  consider  the 
mechanical  viewpoint  in  this  discussion,  keeping  in 
mind  and  giving  due  consideration,  however,  to  the 
matter  of  upkeep  in  specific  cases. 

It  is  doubtless  better  to  consider  tools  from  the 
standpoint  of  the  work  which  they  do  than  in  any 


TOOLS  AND  PATTERNS 


other  way,  although  the  machine  on  wMeh  the  tools 
are  used  will  also  have  a  certain  effect  on  the  group- 
img.  For  example,  a  drill  is  nsed  for  drilling  a  hole 
and  it  is  frequently  used  on  a  drilling  machine  or 
drill  press.  So  also  a  turning  tool  is  used  for  turning, 
a  recessing  tool  for  recessing,  a  threading  tool  for 
threading,  a  reamer  for  reaming,  and  a  file  for  filing. 
It  can  readily  be  seen,  then,  that  the  cutting  operation 
on  the  work  has  a  positive  effect  on  the  name  of  the 
tool.  Some  tools  which  will  be  described  herein,  are 
not  lised  in  machines  but  are  hand  tools,  such  as 
files,  scrapers,  cold  chisels  and  the  like.  Other  tools, 
again,  such  as  surface  plates,  yises,  and  so  on,  can  be 
readily  grouped  under  shop  equipment.  Tools  such 
as  chucks,  face  plates,  tool  holders,  etc.,  form  a  part 
of  the  machine  equipment,  and  are  therefore  classed 
in  this  way.  Other  tools  are  grouped  according  to 
the  kind  of  work  for  which  they  are  intended  or  by 
the  machine  on  which  they  are  to  be  used. 

Any  factory  depends  for  its  success  upon  the  effi- 
ciency of  its  tool  equipment,  and  it  is  therefore  of 
the  highest  importance  that  these  tools  should  be  so 
well  designed,  carefully  made,  and  maintained  that 
no  loss  of  production  can  ever  be  laid  to  their  in- 
efiSciency.  In  discussing  the  purposes  and  applica- 
tion of  tool  equipment  and  kindred  subjects  treated 
here,  cases  will  be  cited  which  are  for  a  large  part 
fundamental  in  their  application.  Complicated  de- 
sign and  intricate  mechaniswis  will  not  be  considered. 
The  cxeeiitiYei  wlio  may  not  be  a  strictly  mechanical 
man,  will  find  that  the  principles  involved  and  the 
iflistances  noted  are  well  wiUun  Im  mechanical  scope. 


HAND  ANB  FORGED  TOOLS 


1 


The  superintendent  or  foreman  may  discover  that 
mechanical  features  are  treated  in  such  a  way  as  to 
bring  out  many  new  points  of  interest.  The  shopman 
and  mechanic  will  appreciate  many  practical  exam- 
ples which  are  given;  and  the  designer  may  profit 
largely  by  his  technical  knowledge  which  will  give 
him  a  more  intimate  understanding  of  many  interest- 
ing points  in  design  treated,  perhaps,  in  an  entirely 
new  way. 

Classiflcation  of  Hand  and  Forged  Tools.— Files, 
cold  chisels,  and  scrapers  are  essentially  hand  tools. 
Hacksaws  also  come  under  this  grouping,  although 
they  are  often  driven  by  power  for  cutting  off  stock 
from  bars.  Forged  tools  are  used  in  so  many  forms 
and  shapes  and  for  so  many  purposes  that  their 
grouping  is  a  difficult  proposition.  On  this  account 
I  have  included  them  in  a  separate  group  in  this 
chapter,  regardless  of  their  shape  or  form  or  the 
class  of  machine  they  are  to  be  used  with.  But  be- 
cause there  are  so  many  shapes  of  forged  tools,  the 
subject  will  be  treated  broadly,  withtMl^  general 
hints  on  the  theory  of  cutting,  the  proper  angles  of 
the  tool,  and  so  on. 

In  the  descriptions  in  this  volume  of  the  various 
tools  I  have  aimed  to  give  principles  and  points  of 
particular  value,  but  I  have  made  no  attempt  to  cite 

my  purpose  has  been 
to  give  a  broad  general  classification  which  will  be 
01  the  greatest  value  without  too  technical  a  treat- 
ment. Important  points  in  connection  with  upkeep 
and  economy  of  operation  wiU  be  noted  from  time 
10  time* 


8 


TOOLS  AND  PATTERNS 


Vlbs. — ^In  general  there  are  three  classes  of  files  in 
connnon  use,  their  dassification  being  de|iendent  upon 
the  kind  of  cnts  which  form  the  teeth.  The  three 
classes  are  rasps,  single  cut,  and  double  cut.  The 
types  or  classes  are  graded  according  to  length  and 
fineness  of  the  teeth  and  are  specified  as  rough,  coarse, 
bastardy  second  cut,  smooth,  and  dead  smooth.  The 
lengths  of  the  various  files  are  from  four  to  sixteen 
inches,  and  each  length  of  each  class  has  its  own 
grade  determined  by  the  number  of  teeth  to  the  inch 
(or  "pitch,"  as  it  is  sometimes  called).  The  fineness 
of  the  teeth  being  proportional  to  the  length  of  the 
file  it  is  evident  that  the  term  second  cut,  for  ex- 
ample, does  not  indicate  the  size  of  the  teeth  unless 
the  length  of  the  file  is  also  known. 

Files  are  of  numerous  forms  to  suit  various  kinds 
of  work,  the  flat,  half  round,  round  or  "rat-tail,'' 
triangular,  and  square  forms  being  most  commonly 
used.  Mies  of  these  varieties  are  full  tapered  or 
tapered  in  both  thickness  and  width  for  about  two- 
thirds  of  their  length,  the  remaining  third  having 
nearly  parallel  edges.  A  warding  file  tapers  in  width 
but  not  in  thickness,  while  pillar  and  hand  files  taper 
in  thickness  but  have  parallel  edges.  Saw  files  and 
equaling  files  are  nearly  of  the  same  size  for  their 
entire  length.  The  tang  of  a  file  is  the  part  to  which 
the  handle  is  fitted  and  the  heel  is  the  part  next  to 
the  tang.  When  one  edge  of  a  file  is  smooth  it  is 
termed  a  "safe"  edge.  The  various  methods  of  cut- 
ting file  teeth  are  shown  in  Figure  1  together  with 
several  cross-sectional  forms. 

Since  files  are  used  for  a  great  variety  of  work  in 


HAND  AND  FORGED  TOOLS 


9 


any  factory  their  cost  becomes  an  item  of  considerable 
importance.  It  behooves  an  executive  to  see  not  only 
that  the  files  ordered  are  of  the  proper  grades,  but 
that  they  are  used  as  they  should  be  and  for  the  work 
for  which  they  are  intended.  It  is  evident,  therefore, 
that  the  selection  of  a  file  for  a  given  piece  of  work 
is  worthy  of  a  certain  amount  of  attention.  For  ex- 
ample, in  selecting  files  for  any  work  it  is  necessary 


1  ill 

RASP                     DOUBLE  CUT             SINGLE  CUT 

FLAT           PILUR    HALF  fKMJND 

ROUND   TRIANGUUR  CROSS 

m.  1.    MLB  FORMS  AND  CLASSES 


to  know  the  kind  of  metal  to  be  cut,  whether  the 
surface  to  be  worked  is  broad  or  narrow,  whether 
the  metal  is  wrought  or  cast,  and  whether  it  is  to  be 
smooth  or  draw-filed  or  wiU  be  finished  in  some  other 
way.  A  rough^ut  or  coarse  file  would  be  used  on  a 
broad  surface  if  much  metal  is  to  be  removed,  and  a 
new  file  would  be  used  rather  than  an  old  one  if  the 
material  is  a  casting.  A  file  which  has  been  some- 
what worn  can  be  used  on  wrought  work  to  advan- 
tage, but  it  would  not  give  good  results  on  a  casting. 
In  general,  thin  files  are  to  be  avoided,  except  in  the 
hands  of  a  skillful  workman,  for  they  are  very  apt  to 
produce  a  rounded  surface. 

In  filing  wrought  metals  a  little  oil  or  turpentine 
may  be  used  on  the  face  of  the  file  so  that  the  file 


10 


TOOLS  AND  PATTERNS 


wai  "take  hold"  better,  but  cast  metals  should 
always  be  cut  dry.  Chalk  rubbed  on  the  file  teeth 
when  filing  castings  will  prevent  clogging,  and  the 
use  of  a  file  eard  (a  wire  bmsli  for  cleaning  the 
teeth)  cannot  be  too  strongly  recommended.  When 
a  file  becomes  clogged  the  depth  of  the  cut  is  reduced 
and  slower  work  is  the  outcome;  and  on  wrought 
metals  chips  will  pack  into  the  file  teeth  and  scratch 
the  work  unless  the  file  is  kept  clean.  Again,  many 
files  are  ruined  by  being  used  on  the  scale  of  a  cast- 
ing; the  edge  of  the  file  only  should  be  used  to  get 
below  the  scale  and  then  the  flat  side  can  be  used  to 
advantage  without  injury  to  the  teeth.  Proper  care 
of  a  file  consists  in  careful  handling,  suitable  selec- 
tion, and  a  thorough  cleaning.  When  oU  or  turpen- 
tine has  been  used  on  a  file^  it  can  be  given  several 
applications  of  chalk  which  will  absorb  the  moisture 
and  bring  out  the  chips  between  the  teeth,  so  that  it 
will  be  clean  and  ready  for  the  next  job  of  work. 

HacikBawi. — Hacksaws  are  of  two  varieties,  those 
used  in  hand-saw  frames  and  those  used  on  power- 
operated  sawing  machines.  A  number  of  years  ago 
hacksaw  teeth  were  punched,  but  at  present  this 
method  is  little  used  and  the  teeth  are  now  milled. 
The  hacksaw  blade  used  in  hand  hacksaw  frames  is 
little  different  from  the  machine  saw  blade  except 
that  it  lighter  and  not  adapted  to  such  heavy  service. 
The  teeth  of  hacksaws  are  "set"  in  different  ways 
to  suit  different  cutting  requirements,  and  the  prac- 
tice of  various  manufacturers  differs  somewhat  in 
this  regard.  For  example,  considering  the  teeth  as 
set  over  an  each  side  of  an  imaginary  center  line,  one 


HAND  AND  FORGED  TOOLS 


iJli  "til 


maufacturer  may  make  a  saw  blade  with  every  alter- 
nate tooth  set  out  from  each  side  of  the  line;  another 
may  be  made  with  two  teeth  set  out  the  same  dis- 
tance from  the  center  line  and  an  intermediate  tooth 
on  the  center  line;  a  third  variety  may  have  two 
teeth  on  one  side,  one  tooth  on  the  center  and  then 
two  teeth  on  the  other  side;  while  still  another  may 
have  one  tooth  set  out  a  certain  distance  on  one  side 
of  the  center  line,  the  next  tooth  set  out  the  same  dis- 
tance on  the  other  side  of  the  center  line,  then  two 
teeth  set  out  not  quite  as  far  on  each  side  of  the 
center  line  and  a  fifth  tooth  set  on  center.  These 
variations  in  the  setting  of  the  teeth  are  not  followed 
to  any  great  degree  by  different  manufacturers,  al- 
though certain  claims  in  regard  to  their  value  for 
different  classes  of  materials  may  have  considerable 
value. 

Ordinarily  hacksaw  blades  have  one  tooth  set  to 
the  right,  the  next  to  the  left,  and  the  third  one  on 
the  center  line.  The  teeth  which  are  set  out  from  the 
center  widen  and  deepen  the  cut  of  the  saw,  while  the 
straight  teeth  in  the  center  tend  to  keep  the  cut  free 
from  chips.  The  tooth  spacings  commonly  used  vary 
from  nine  teeth  to  the  inch  to  thirty-two  teeth  to  the 
mch.  Speaking  generally,  saws  having  the  coarser 
spacing  should  be  used  on  soft  materials,  such  as 
wood,  fibre,  or  soft  metal.  The  finer  spacings  are 
better  for  hard  metal,  because  they  are  less  likely  to 
strip.''  For  the  average  work  in  the  machine  shop 
for  hand  work  blades  having  eighteen  teeth  to  the 
inch  are  recommended,  while  for  machiiillllillii:  blades 
with  twelve  to  fourteen  teeth  to  the  inch  are  most 


12 


TOOLS  AND  PATTERNS 


9- TEETH  TO  THE  INCH 


WWL.  2.    TOOTH  SPACING  IN  HACK-SAW  BLADES 
(Slightly  Reduced) 

eeonomical.  A  eomparison  of  the  tooth  spaeings  wiU 
be  found  in  Figure  2. 

To  obtain  the  best  results  in  using  hacksaws, 
whether  for  machine  or  hand  work,  the  blade  should 
be  well  strained  in  the  frame  to  insure  tme  cutting 
and  to  prevent  breakage.  The  selection  of  the  proper 
saw  blade  for  a  given  class  of  work  makes  a  great 
difference  in  the  efficiency  obtained. 

Cold  CSdseb.— ^Id  chisels  are  made  in  many  forms 
and  for  various  classes  of  work,  such  as  chipping, 
key-seatingy  oil-grooving,  cornering,  and  prick-punch- 
ing for  correcting  errors  in  drilling  and  also  for  lay- 
ing out  work  to  be  machined.  When  castings  are 
received  from  the  foundry,  often  they  will  be  found 
with  ragged  edges  or  other  inequalities  which,  unless 
removed  before  machiningi  wonld  interfere  with  their 


HAND  AND  FORGED  TOOLS 


13 


handling.  Several  methods  are  used  to  smooth  up 
the  surfaces;  small  castings  are  snagged'^  on  a 
coarse  grinding  wheel  which  is  mounted  on  a  spindle 
in  a  heavy  floor  stand;  larger  work  is  roughed  off 
with  a  smaller  wheel,  one  that  may  be  operated  by  a 
flexible  shaft  suitably  counterbalanced  to  facilitate 
handling  or  mounted  on  a  small  truck  and  operated 
by  an  electric  motor.  Or  large  work  may  be  chipped 
with  a  cold  chisel,  usually  one  operated  by  compressed 
air  in  a  chipping  hanamer,  or  by  hand  in  some  cases. 
Compressed-air  chipping  hammers  are  very  rapid  in 
their  action  and  can  be  made  to  cover  a  considerable 
amount  of  surface  in  a  remarkably  short  time.  Hand- 
chipping  operations  are  much  slower  but  can  be  used 
for  purposes  not  adapted  to  machine  chipping. 

A  number  of  forms  of  cold  chisels  are  shown  in 
Figure  3.  The  tool.  A,  is  known  as  a  flat  chisel;  B, 
a  cape  chisel;  C,  a  round  nose  chisel  or  gouge;  D,  the 
cow-mouth;  E,  diamond  point,  and  F,  a  straight-side 
chisel.  An  important  point  in  connection  with  cold 
chisels  is  the  angle  of  the  edges  in  relation  to  the 
cutting  point,  as  these  edges  serve  as  guides  in  chip- 
ping  operations.  Figure  4  shows,  at  A  and  B,  the 
manner  in  which  these  edges  act  as  guides  when  work 
IS  being  done.  Taking  the  flat  chisel  as  an  example 
and  referring  to  the  diagram  shown  in  Figure  4,  it 
wiU  be  seen  that  the  angle  of  the  edge,  as  indicated 
at  A,  tends  to  shear  the  metal  on  the  upper  side  and 
acts  as  a  guide  on  the  lower  surface  of  the  chisel  to 
prevent  too  deep  cutting.  In  the  example  B,  the  tool 
lias  been  ground  incorrectly,  so  that  there  is  no  shear- 
ing  action  on  the  metal  and  the  tendency  is  for  the 


14                  TOOLS  AND  PATTERNS 
I  


A- 

, — —  I.,'.. — 

— 

B  ' 

— D 

 C-' 

—zi— 

E* 

II  ^ 

im.  3.    DIFFERENT  FORMS  OF  COLD  CHISELS 

cbisel  to  gouge  down  into  the  work  and  not  prodnce 
a  good  cutting  action. 

Tlie  cape  cMsel,  B,  in  Figure  3,  is  made  so  that  the 
point  is  narrow  and  tapi>ers  back  slightly  to  give 
clearance  when  cutting  a  key  way  or  something  of 
this  kind.  This  clearance  also  prevents  upsetting  the 
metal  and  raising  a  bnrr  along  the  edges  of  the  groove. 
So  also  the  gonge,  C,  has  a  slight  amount  of  back  clear- 
ance to  facilitate  the  cutting  action.    This  type  of 


HAND  AND  FORGED  TOOLS 


15 


'  Shearing  Anqfe 


Giiidtng  £cfge  A-'' 


FIG.  4.  EFFECT  FROM  INCORRECT  AND  CORRECT  ANGLES  ON 

GOU)  CHISELS 

chisel  is  used  largely  for  cutting  oil  grooves  in  bear- 
ings, pulleys,  and  similar  work.  It  will  be  seen  that 
this  type  of  chisel  is  ground  at  a  different  angle  than 
the  cape  and  flat  chisels.  This  is  done  so  as  to  per- 
mit the  operator  to  change  the  depth  of  the  cut  by 
raising  the  end  of  the  chisel  a  trifle  while  in  use. 
The  cow-mouth  chisel  is  used  for  chipping  circular 
work;  while  the  diamond  point,  shown  at  E,  is  used 
for  correcting  errors  when  drilling  holes,  for  chip- 
ping in  the  corners  of  dies,  and  such  work.  The 
straight-side  chisel,  shown  at  F,  is  commonly  used  by 
die  makers  for  squaring  up  the  sides  of  punches  and 
dies  and  for  squaring  out  holes,  cutting  shoulders, 
and  the  like. 

Scrapers. — ^After  a  piece  of  work  has  been  ma- 
chined, the  eye  is  deceived  into  thinking  that  the 
resulting  plane  surface  is  smooth  and  free  from 
humps  and  hollows.    As  a  matter  of  fact,  however, 


16 


TOOLS  AND  PATTERNS 


the  apparently  smooth  surface  is  much  like  the  waves 
of  the  ocean  on  a  small  seale;  hence,  if  it  is  neces- 
sary to  have  a  perfectly  fitting  piece  of  work,  the 
**high  spots''  must  be  removed  and  the  whole  sur- 
face worked  down  more  nearly  level.  These  high 
spots  can  only  be  levelled  by  hand  with  scraping 
tools.  It  may  seem  strange  to  the  layman  that  a 
piece  of  work,  if  properly  clamped,  cannot  be  finished 
to  a  true  surface  on  a  high  class  machine  tqol,  and 
if  the  machine  tool  itself  is  in  first  class  working 
condition,  but  even  under  the  most  favorable  con- 
ditions there  is  bound  to  be  a  certain  amount  of 
spring"  both  in  the  work  being  machined  and  in 
the  tool  which  is  cutting  it  Hence,  work  which  has 
been  machined  shows  an  infinite  number  of  high  and 
low  spots  more  or  less  evenly  distributed  over  the 
surface.  If  two  moving  parts  were  to  be  fitted  to- 
gether with  these  high  and  low  spots  still  upon  them, 
it  would  only  be  a  short  time  before  the  wearing 
down  of  the  spots  would  destroy  the  alignment  of  the 
pieces,  seriously  impairing  their  accuracy.  As  an 
example,  consider  the  ''ways''  of  a  planer  or  of  a 
turret  lathe:  In  the  planer,  if  the  ways  were  not 
scraped  to  a  perfect  bearing  one  side  would  be  very 
apt  to  wear  more  than  the  other,  so  that  the  work 
produced  would  not  be  aoenrate-^it  might  be  taper- 
ing, convex,  concave,  or  even  a  combination  of  all 
inaccuracies  mentioned.  In  the  case  of  the  turret 
lathe,  the  center  of  the  turret  would  not  line  with  the 
spindle  after  a  short  while,  and  the  holes  bored  and 
surfaces  turned  would  be  tapering  or  otherwise  dis- 
torted. 


HAND  AND  FORGED  TOOLS 


17 


It  will  be  seen  from  the  foregoing  that  on  flat  work 
it  is  necessary  to  scrape  all  surfaces  which  are  to  be 
in  moving  contact  with  other  flat  surfaces.  When 
their  contact  is  with  cylindrical  bearings,  they  may 
be  scraped,  lapped,  or  ground  according  to  the  par- 
ticular requirements.  The  art  of  scraping  requires 
practice,  a  nice  sense  of  touch,  and  a  considerable 
amount  of  judgment.  Many  people  not  conversant 
with  the  necessity  of  scraping  bearing  surfaces, 
imagine  that  the  mottled  effect  produced  is  for  orna- 
mental purposes,  yet  it  is  highly  essential  on  any 
well-made  machine  and  serves  no  other  purpose  than 
that  menticaed. 

Many  varieties  of  scrapers  have  been  designed 
simply  to  fulfill  a  need  for  a  tool  to  get  at  some  par- 
ticular piece  of  work  of  unusual  form  on  which  a 
bearing  was  desired.  In  Figure  5  is  shown  a  double- 
end  scraper.  A,  commonly  used  on  plane  surfaces  and 
broad  work.  It  wiU  be  seem  that  this  type  has  a 
broad  flat  surface  and  is  perfectly  square  across  the 
end.  Such  scrapers  are  often  made  single-ended  from 
an  old  file,  having  a  wooden  handle  on  one  end;  but  for 
heavy  work  the  double-end  tool  shown  is  to  be  pre- 
ferred, for  it  is  not  Ukely  to  spring  itillllts  weight 
gives  an  added  advantage.  It  is  important  that  any 
scraper  of  this  type  should  be  ground  perfectly 
square  across  the  end  so  that  it  will  not  tend  to  gouge 
work  when  in  use. 

Scrapers  are  hardened  to  as  high  a  degree  as  fire  and 
water  and  the  metal  itself  will  permit.  The  scraper,  B, 
in  Figure  5  is  hook  shaped,  which  permits  it  to  be 
pulled  toward  the  workman  instead  of  pushed  away 


18 


TOOLS  AND  PATTERNS 


no.  5.    YABIODB  TYFE8  (NT  BGEAFBH3 


from  him,  as  in  the  case  of  the  double-end  scraper.  The 
triangular  form,  C,  is  sometimes  made  from  a  three, 
cornered  file  from  whieh  the  teeth  have  been  ground 
away.  All  scrapers  are  made  of  high-grade  steel,  as 
the  service  to  which  they  are  put  is  so  severe  that  no 
economy  would  be  found  in  using  low-grade  steel  for 
the  parpose.  Scrapers  of  the  three-cornered  variety 
are  largely  used  for  scraping  bearings  of  cylindrical 
form,  such  as  the  crank-shaft  hearings  in  an  auto- 
mobile, or  spindle  bearings  in  machine  tools. 

When  flat  surfaces  are  to  be  scraped,  a  "master'' 
or  standard  surface  plate  is  used  and  the  parts  to  be 
fitted  are  rubbed  on  it  to  determine  the  high  spots. 
In  using  this  master  plate  a  very  light  coating  of 
Prussian  blue,  red  lead,  or  lamp  black  is  spread  upon 
the  machined  work  which  is  then  rubbed  upon  the 
master  plate;  the  high  spots  on  the  machined  piece 
show  bright  and  are  removed  with  the  scraper.  This 
performance  is  repeated  until  the  work  shows  an 
even  bearing  all  over.  When  completed  a  series  of 
high-point  bearing  spots  very  close  together  is  ob- 


HAND  AND  FOB0ED  TOOLS  19 


tained  all  over  the  work,  so  that  it  has  the  mottled 
appearance  previously  mentioned. 

Forged  Tools. — ^All  varieties  of  work  on  nearly 
every  class  of  machine  tool  require  the  use  of  forged 
tools.  Many  shapes  and  forms  are  adopted,  depend- 
ing on  the  work  for  which  they  are  intended.  Gen- 
erally speaking,  their  construction  is  such  that  they 
can  be  ground  several  times  before  reforging  is  neces- 
sary. On  lathes  and  planers  they  are  used  to  a 
greater  extent  than  on  any  other  classes  of  machines, 
and  many  tools  of  the  same  general  type  can  be  used 
on  these  two  machines. 

A  group  of  lathe  and  planer  tools,  which  may  be 
considered  as  representative  types  is  shown  in  Figure 
6,  although  many  modifications  are  required  to  suit 
particular  cases.  It  is  unnecessary  to  take  up 
of  the  tools  illustrated  and  describe  its  functions,  for 
the  reason  that  tools  of  this  kind  are  so  well  known 
that  they  require  little  description  and  can  be  found 


na.  6.  A  GBoup  o?  fobged  tools 


W  TOOLS  AND  PATTEBNS 

in  every  modern  f aetory  as  weU  as  in  those  of  older 
davs. 

The  matter  of  upkeep  of  cutting  tools,  however,  is 
a  subject  which  should  receive  most  careful  attention; 
and  as  the  upkeep  and  productive  capacity  of  any 
tool  is  dependent  upon  its  shape  we  will  consider  the 
points  which  are  important  in  regard  to  cutting 
angles  and  i^apes  of  the  several  varieties  of  tools. 

It  is  evident  that  any  kind  of  cutting  tool,  to  pro- 
duce its  maximum  amount  of  work,  should  be  so 
shaped  and  ground  that  it  will  remove  the  metal  with 
the  least  possible  amount  of  friction.  When  such  a 
condition  is  reached  the  machine  tool  is  at  its  best, 
and  the  work  is  produced  with  a  minimum  amount 
of  labor.  Further  than  this,  the  life  of  the  tool  is 
pndonged  because  the  periods  of  regrinding  are 
lessened. 

The  simplest  types  of  tools  are  used  on  planer 
work,  for  the  reason  that  the  cutting  action  of  the 
planer  is  along  a  straight  line.  On  the  other  hand, 
a  lathe  tool  is  also  used  on  the  outside  of  cylindrical 
work,  in  boring  a  hole,  or  in  turning  a  taper,  so  that 
in  each  case  the  tool  must  be  differently  shaped  in 
order  to  clear  itself  and  ^Hum  the  cMp"  to  the  best 
advantage. 

A  number  of  factors  must  be  considered  in  the  de- 
sign of  cutting  tools,  such  as  the  position  of  the  tool 
in  relation  to  the  work,  the  spring  of  the  tool  under 
the  cutting  action,  the  shape  of  the  work,  and  the 
material  to  be  cut.  For  example,  soft  and  fibrous 
materials  require  an  entirely  different  cutting  angle 
than  do  materials  having  a  short-grained  structure. 


HAND  AND  FOBGED  TOOLS 


21 


The  tool.  A,  shown  in  Figure  7,  is  seen  to  be  im* 
properly  designed  for  planer  work,  because  an  excess 
of  power  is  required  to  pull  the  tool  and,  further- 
more, it  really  does  not  cut  at  all  but  crowds  or 
pushes  the  metal  off.  If  such  a  tool  were  used  for  a 
long  while  under  the  condition  shown  it  would  in 


wo.  7.    THE  CUTTING  ACTION  OF  PLANER  T00U3 

(A)  Incorrect  Form  of  Cutting  Tool.   (D)  Abrasive  Action  of 

Chips  on  Face  of  Tool. 

time  develop  a  form  similar  to  that  shown  at  D  in 
the  illustration,  because  of  the  abrasive  action  of  the 
chips  against  the  tool.  It  would  be  perfectly  logical 
to  assume,  then,  that  if  the  tool  were  ground  to  this 
shape  in  the  first  place  its  form  would  be  more  nearly 
correct. 

The  manner  in  which  any  cutting  tool  is  supported 
determines  to  a  certain  extent  its  shape,  because  the 
spring  of  the  tool  holder  may  tend  to  carry  it  into 


22 


TOOLS  AND  PATTERNS 


the  work  and  produce  chatter/'  An  example  of 
this  kind  is  illustrated  in  the  planer  tool.  A,  Figure 
&  As  the  work  moves  in  the  direction  indicated  by 
the  arrow,  the  tool  and  tool  block  together  will 
spring  (if  sufficient  pressure  is  applied),  radially  from 
the  corner  B  with  a  tendency  to  dig  into  the  work. 


1 

m.8.  FliAKEBtOOIB 

CA)  The  Digging  Tendency  of  Tools  ProdiictiTe  of  Chatter. 
(C)  Tool  Siirings  Away  ftom  Work  and  X>oes  Not  Dig  in. 

For  this  reason  the  tool  may  be  made  as  shown  at  C, 
with  the  cutting  point  far  enough  back  so  that  any 
spring  action  will  carry  the  tool  away  from  the  work, 
thus  obviating  chatter."  The  heel  angle  of  a  cut- 
ting tool  should  be  of  such  shape  as  to  resist  the 
cutting  strain  to  the  best  advantage.  It  is  obvious, 
therefore,  that  heavy  cutting  tools,  such  as  those 
used  on  a  planer,  should  have  a  greater  body  of  metal 
and  less  clearance  behind  the  cutting  edge  than  those 
used  for  a  lighter  class  of  work. 

The  diamond-point  tool,  shown  in  Figure  9,  is  a 
common  type  of  lathe  tool,  but  such  a  tool  is  limited 


HAND  AND  FOBGfiD  TOOLS 


23 


in  its  productive  capacity  by  the  width  of  the  cut- 
ting face  and  the  strength  of  the  neck.  It  is  not 
suited  to  high-speed  work  nor  to  fine  finishing,  ex- 
cept on  wiry  material  such  as  tool  steel  or  alloy 
steels.  In  work  of  this  nature  it  may  be  used  for 
finishing,  providing  that  a  very  fine  feed  is  given 


MG.  9.    DIAMOND-POINT  FIG.   10.     SIDE  TOOL  FOR 


LATHE  TOOL  ROUOmNG  DOWN  WORK 

the  machine  tool  and  a  sUght  "drag"  is  stoned  just 
behind  the  cutting  point  so  as  to  produce  a  burnish- 
mg  effect  on  the  work.  Many  mechanics  use  a  side 
tool  such  as  that  shown  in  Figure  10  for  roughing, 
down  bar  stock,  for  the  cutting  face  of  the  tool  is 
wide  and  it  can  be  made  to  take  a  very  wide  chip  if 
set  as  indicated  in  the  illustration. 

In  addition  to  the  points  above  mentioned,  when  a 
cutting  tool  is  to  be  used  on  cylindrical  surfaces,  as 
m  the  case  of  a  lathe  job,  the  position  of  the  tool 
relative  to  the  center  of  the  work  is  of  importance, 
iheoretically  a  tool  should  be  **on  center,''  whether 
It  is  boring  a  hole  or  turning  an  outside  cylindrical 
surface.  Ijt  must  be  remembered,  however,  that  the 
inajority  of  tools  are  more  or  less  elastic  and  will 
show  a  certain  amount  of  spring  which  must  be  taken 


24 


TOOLS  AND  PATTERNS 


into  consideration  in  setting  the  tool.  Hence,  if  an 
outside  diameter  is  to  be  tnmedy  for  example,  the 
tool  should  be  set  slightly  below  center  so  that  it 
will  not  dig  in  under  the  pressure  of  the  cut  but  will 
rather  tend  to  spring  away  from  the  work.  Similarly, 
in  boring  a  hole  the  tool  should  be  slightly  abov^ 
center  so  that  its  spring  under  the  cutting  action 
will  also  carry  it  away  from  the  work.  But  as  previ- 
ously mentioned  these  points  will  depend  entirely  upon 
the  manner  in  which  the  tools  are  supported  and  upon 
the  direction  which  their  deflection  will  take  under  the 
cutting  strain. 

Grinding  Tools.— In  past  years  it  has  been  the 
custom  for  mechanics  to  grind  their  own  tools  to  any 
particular  kind  of  a  shape  that  they  fancied  gave  the 
best  results.  The  natural  consequence  of  a  procedure 
like  this  was  that  one  man's  work  would  be  much 
superior  to  another's  because  of  a  greater  knowledge 
of  tool  shaping.  At  present,  however,  it  is  possible 
to  purchase  a  tool  grinder  for  forged  tools  so  that 
all  tools  of  any  particular  variety  can  be  ground  to 
a  predetermined  angle,  even  by  an  inexperienced  man. 
The  work  produced  with  tools  uniformly  ground  is 
much  superior  to  that  done  by  a  "hit  or  miss'' 
method,  and  the  life  of  the  tool  is  correspondingly 
prolonged.  In  addition,  the  amount  of  time  lost  in 
regrinding  tools  is  greatly  reduced  and  the  labor  of 
a  skilled  mechanic  is  not  required.  In  determining 
proper  angles  for  cutting  tools  the  aim  should  he 
toward  the  ideal  form  which  will  turn  the  chip  to  the 
best  advantage  with  the  least  amount  of  power  and 
at  the  same  time  to  give  the  longest  life  to  the  tool. 


HAND  AND  FOBGED  TOOLS 


25 


Especial  caution  should  be  exercised  not  to  obtain 
an  angle  so  sharp  that  the  cutting  edge  will  approach 
the  wood  tool  in  shape,  for  a  tool  with  such  an  edge 
would  have  a  very  short  life  and  would  require  fre- 
quent regrinding. 

Tools  for  Holders.— In  order  to  economize  in  the 
amount  of  high-speed  steel  used  in  forged  tools  a 
number  of  holders  have  been  devised  which  require 
only  small  sections  of  such  steel.    These  holders  are 
so  arranged  that  they  will  take  stock  of  standard 
sizes  and  clamp  them  securely;  in  this  manner  they 
will  answer  many  purposes  of  forged  tools  made  from 
high-speed  steel,  or  certain  clesses  of  work  they  are 
extremely  valuable;  but  for  very  heavy  cutting  forged 
tools  are  still  preferred  in  many  factories  because 
the  heavy  forged  tools  have  a  greater  section  and 
carry  away  the  heat  more  rapidly  than  the  smaller 
sections  used  in  holders,  and  are  therefore  capable  of 
higher  speeds  and  greater  production.    This  fact, 
however,  does  not  detract  in  any  way  from  the  utility 
and  economy  of  the  holders  mentioned.  These  holders 
will  be  described  in  more  specific  detail  in  the  dis- 
cussion of  tool  holders* 


BBOP  FORGING  AND  BLANKING  DIES 

Principlet  nf  Drop  Fixrgiif.— rMtho^  drop  f org- 
ing  di«,  may  be  HM^nt  when  they  become  greatly 

worn,  they  should  still  be  considered  as  perishable 
tools;  a  great  deal  depends  upon  the  treatment  of  the 
die,  botli  in  the  process  of  hardening  and  also  in  its 
use.  The  eonstmction  and  form  of  the  die  itself 
makes  a  great  difference  in  its  life,  and  it  is  difficult 
to  estimate  the  number  of  pieces  upon  which  any  die 
can  be  used  on  account  of  the  variations  in  the  form 
of  pieces  to  be  drop  forged.  When  a  comparatively 
small  number  of  pieces  are  to  be  made,  it  is  possible 
to  make  up  cast  iron  dies,  but  of  course  these  are 
not  serviceable  for  any  length  of  time.  When  only 
six  or  eight  similar  pieces  are  to  he  made  cast  iron 
dies  are  most  economical.  But  in  work  requiring  a 
large  production  the  dies  are  made  of  steel  containing 
from  0.45  to  0.60  per  cent  carbon,  and  the  blocks  from 
which  they  are  cut  range  between  5  and  8  inches  in 
thickness.  Usually  the  dies  are  dovetailed,  as  shown 
in  Figure  11,  to  fit  the  drop  hanmier  in  which  they  are 
to  be  used. 

Since  the  advent  of  the  automobile,  drop  forging 
processes  have  been  greatly  perfected,  and  many 
forgings  are  now  made  which  would  have  been  con- 


DBOP  FOifcaiNa  AND  DIBS  tT 


2  I 


FIG.  11.    DOVE-TAILED  DROP  FORGE  DIES 

sidered  impracticable  a  few  years  ago.  The  necessity 
^  for  extraordinary  strength  in  certain  parts  has  led 
to  the  adoption  of  alloy  steels  for  these  pieces  and 
drop  forgings  are  made  to  suit  the  conditions. 

Comparatively  few  pieces  of  work  have  a  form 
such  that  they  can  be  produced  in  a  single  pair  of 
dies.  When  the  diameters  do  not  vary  greatly  in  the 
different  sections,  circular  forms  can  be  made  in  a 
single  set  of  dies;  but  forms  of  widely  varjdng  sec- 
tion require  a  preliminary  "breaking  down*'  opera- 
tion, and  when  a  heavy  boss  is  a  part  of  the  forging 
three  or  four  operations  may  be  necessary  before  the 
piece  is  completed.    When  the  forgings  are  small. 


TOOLS  AND  PATTERNS 


several  recesses  can  be  made  in  one  set  of  dies  for 
breaking  down,  formation,  cutting  off,  and  nicking 
for  breaking  off.  Generally  speaking,  it  is  best  to 
complete  a  lorging  At  a  single  heat  if  possible,  but  in 
some  instances  sieveral  heats  may  be  necessary.  When 
work  is  of  large  size  and  two  or  more  sets  of  dies  are 
nsed,  the  hammers  can  be  placed  near  each  other,  so 
that  the  workman  can  step  immediately  from  one  to 
lie  other  without  "losing  the  heat/' 

In  work  done  on  the  anvil  by  hand  the  smith  acts 
as  an  artist  and  models  his  work  to  the  form  re- 
quired, drawing  it  out  here  or  there  as  the  design  may 
call  for.  But  when  forgings  are  made  in  dies,  the 
amount  of  metal  from  which  a  piece  is  stamped  must 
be  large  enough  so  that  it  will  overrun  the  die  a 
trifle,  thus  assuring  a  full  die  and  a  forging  of  proper 
shape.  The  "fin"  which  is  squeezed  out  between  the 
dies  at  the  time  of  forging  must  be  removed  by  means 
of  trimming  dies.  Provision  is  made  in  the  dies 
themselves  to  take  care  of  this  fin,  as  shown  in 
Kgure  12.  A  wide  and  rather  shallow  groove  which 
is  cut  all  around  to  receive  the  fin  is  shown  at  A,  and 
the  manner  in  which  the  faces  of  the  dies  are  some- 
times sloped  away  for  the  same  purpose  is  shown  at 
B.  Figure  13  shows  a  forging  of  a  lever  which  has 
the  fin,  X,  still  on  it,  and  the  trimming  die,  shown 
in  the  lower  part  of  illustration,  shears  off  the  fin 
and  leaves  the  forging  clean  and  ready  for  use. 

Cylindrical  work  can  be  manipulated  by  the  oper- 
ator so  that  no  fin  will  be  left  by  simply  rotating  the 
work  under  the  hammer  during  the  process  of  forg- 
ing. Drop-forged  levers  are  frequently  made  with  a 


DROP  FOmaiNd  AND  DIBS  ^ 


S  2 


vm.  12.  imm  vobge  die  with  space  wm  becetving  mns 

countersunk  portion  in  the  center  of  the  bosses  in 
order  to  facilitate  machining,  as  shown  in  **A''  of 
Figure  14.  Other  cases  when  the  hole  itself  can  be 
punched  directly  through  the  work  are  indicated  in 
the  dies  shown  at  **B''  in  the  same  illustration.  Oc- 
casionally the  hole  in  the  boss  is  taken  care  of  by 
the  method  shown  at  "C*;  this  leaves  a  thin  web 
at  the  center  of  the  hole,  which  is  afterwards  punched 
out  without  difficulty.  So  many  forms  of  dies  and 
forgings  for  all  classes  of  work  occur  that  it  is 
obviously  out  of  the  question  to  do  more  than  out- 
line the  simple  form  so  as  to  give  an  approximation 
of  the  method  of  treatment. 

Blanking  Dies.— When  work  is  produced  from  cold 
metal  the  processes  used  for  shaping  the  forms  are 


TOOLS  AND  PATTSMMB 


na.  13.  A  ROUGH  raunNO  and  vm  wmmiko  dis 
very  different  from  those  previously  described  under 
the  head  of  drop  forgings.  Cutting  *dies  should 
properly  include  all  types  which  punch  or  cut  out 
various  shapes  from  the  metal  as  it  is  fed  through 
the  press  when  the  section  of  the  metal  itself  is  not 
changed  to  any  extent  Shaping  dies  on  the  contrary 
include  any  which  change  the  form  of  the  metal  from 
its  original  flat  condition  to  one  of  a  different  con- 
tour in  which  the  various  surfaces  are  in  different 
planes.  Some  dies  of  the  latter  class  really  constitute 
a  combination  of  cutting  and  shaping  dies — ^the  work 
is  first  punched  out  to  shape  and  is  afterwards 
formed. 

Follow  dies  are  dies  which  have  two  or  more  cut- 
ting portions  acting  progressively  on  the  work  as  it 


DBOP  WOmmQ  AND  DIBS 


31 


TO.  14.    METHODS  OP  ^ROVTOING  FOR  HOLES  IN  DROP  FORGINGS 


is  fed  through  the  press,  each  stroke  producing  a 
finished  piece.  Dies  of  this  kind  are  sometimes  called 
tandem  dies.  An  example  of  this  die  is  shown  in 
Figure  15.  It  will  be  seen  that  the  work  **A''  has 
three  separate  operations  all  performed  upon  it  in 
the  same  die,  and  yet  at  each  stroke  of  the  press  a 
completed  piece  is  turned  out. 

Gang  dies,  are  often  used  for  small  parts  in  order 
to  save  waste  metal  and,  at  the  same  time,  to  produce 
work  more  rapidly.  An  example  is.  shown  in  Figure 
16.  This  illustration  shows  that  several  pieces  may 
he  made  at  one  stroke  of  the  press  with  a  compara- 
tively  small  amount  of  wasted  metal. 

A  compound  die  is  one  that  is  arranged  in  such  a 
way  that  the  punch  and  die  portions  are  not  separ- 
ated but  are  combined  in  such  manner  that  the  upper 


fOOIiS  AND  PATTEBNE 


O 

nil ISHCO  WORK 


STOCK  AFTER  BLANKW6 


1  PUNCH 

II 

1  u 

1 

i 

0I£ 


0 

o 

Q.. 

o,  ■>, 

0 

PLAN  VIEW  OF  DIE 


FHi.  15.  mvuiMnMmkmsiAJmmvmmsmmwx. 

and  lower  half  e^ch  contam  a  puncli  and  die.  Such  a 
die  has  its  stripper  springs  adjusted  so  that  they  are 
strong  enough  to  overcome  the  cutting  resistance  of 
the  stock,  after  which  they  are  compressed  untU  the 
end  of  the  stroke  is  reached.  In  a  compound  die  all 
the  operations  are  carried  out  synchronously  while 
the  stock  is  firmly  held;  therefore,  the  work  pro- 
duced hy  this  type  of  die  is  more  accurate  than  those 
previously  described.  It  is  not  as  simple  a  die,  how- 
ever, and  it  requires  much  more  care  in  setting  up. 

Forming  dies  are  used  for  work  of  hollow  form,  a 
cavity  being  made  in  the  die  into  which  the  work  is 


DBOF  FOB€HNa  AND  DIBS 


33 


FIRST  OPERATION 


SECOND  OPERATION 

PUNCH 


i 

Ms 

WG.  16.    AN  EXAMPIiE  OP  A  GANG  ME 

forced  by  the  press.  Drawing  dies  are  used  for  much 
the  same  class  of  work  as  forming  dies;  but  in  the 
process  of  drawing,  the  flat  blank  which  is  being 
formed  is  held  rigidly  between  the  surfaces  of  the 
die  so  that  wrinkles  will  not  form  during  the  draw- 
ing operation.  Curling  dies  and  bending  dies  are 
used  respectively  for  turning  over  the  edges  of  sheet 


X 


TOOLS  AND  PATTERNS 


metal  pieces  and  tm  besding  the  snrfaee  of  H  piece 
of  work  into  a  partial  curve,  not,  however,  a  com- 
plete circle. 

Sub-press  dies,  strictly  speaking,  are  not  a  special 
class  of  die  except  in  the  sense  that  the  pnnch  and 
die  are  combined  in  a  single  unit  by  means  of  guides 
so  that  there  is  no  necessity  for  lining  up  the  lower 
and  upper  dies  when  setting  up.  A  high  degree  of 
accuracy  is  assured  when  this  class  of  die  is  used, 
although  the  expense  of  the  die  itself  may  be  some- 
what greater. 


CHAPTER  III 


BULLING,  BORING,  AND  BEAMING 

DriU8.~^Drills  may  be  considered  as  one  of  the 
most  important  factors  in  producing  work  in  any 
manufacturing  plant.  A  drill  must  not  be  considered 
as  a  finishing  tool,  however,  although  it  is  possible, 
if  the  drill  is  carefully  ground  and  the  work  pain- 
stakingly  performed,  to  produce  a  clean  hole  quite 
close  to  the  size  of  the  tool.  For  many  classes  of 
work  a  drilled  hole  answers  every  purpose,  and  if 
followed  by  a  reamer  a  smooth  hole  of  any  required 
diameter  may  be  readily  produced.  For  bolts  or 
other  fastenings  of  similar  character  a  drilled  hole  is 
usually  considered  commercially  good. 

As  in  other  types  of  tools,  drill  shapes  and  forms 
are  dependent  to  a  certain  extent  on  the  class  of 
material  upon  which  they  are  to  be  used.  Almost 
any  kind  of  a  pointed  tool  will  drill  a  hole  if  revolved 
under  pressure,  but  in  order  to  produce  the  work 
properly  the  drill  shape  must  be  suited  to  the  material 
to  be  cut.  As  a  preliminary  operation  in  drilling  a 
long  hole,  it  is  often  advisable  to  spot  the  material 
with  a  short  drill.  The  stiffness  of  the  short  tool  is 
an  advantage  to  start  the  hole  in  the  right  place  and 
not  run  any  chance  of  the  deflection  which  might  take 
place  if  a  long  drill  were  to  be  used  first.  Further- 

S5 


36 


TOOLS  AND  PATTERNS 


more,  a  considerable 'saving  in  drill  grinding  will 
result,  as  the  short  drill  gets  through  the  scale  on 
the  work  and  leaves  the  long  drill  to  take  a  clean 
cut  under  the  snrface  of  the  scale.  This  treatment  is 
of  marked  advantage  in  drilling  forgings  on  the 
turret  lathe.  * 

Drills  in  common  nse  are  shown  in  Figure  17.  The 
spotting  drill,  A,  is  groond  to  an  angle  of  40  degrees 
in  order  that  the  following  drill  may  commence  its 
cut  on  the  lips  and  not  on  the  point;  it  will  then  cut 
more  freely  and  get  a  better  start  in  the  work.  The 
maimer  in  which  the  cutting  action  takes  place  with 
the  following  drill  is  clearly  shown  in  the  diagram 
at  B. 

The  drill,  C,  is  Uttle  used  in  general  manufacturing, 


ma.  17.  VARIOUS  types  of  maiA 


DRILLING,  BORING,  FORGING  37 


but  it  is  an  important  item  in  the  equipment  of  the 
blacksmith  or  metal  worker.  A  drill  of  this  type  is 
not  suited  to  deep  holes,  although  is  particularly 
adapted  to  thin  work.  It  has  no  twist,  and  there- 
fore does  not  have  a  tendency  to  tear  and  break  the 
metal  as  it  passes  through  the  work.  The  wood  drill, 
D,  is  often  used  by  cabinet  makers  and  other  wood 
workers.  This  drill  also  has  no  twist,  but  is  partly 
cylindrical  with  a  groove  for  chips  on  each  side. 

The  ordinary  type  of  twist  drill,  E,  is  used  in 
general  manufacturing  work.  The  angle  at  which  it 
is  usually  ground,  indicated  in  the  illustration,  is 
about  31  degrees,  but  the  angle  of  the  twist  cut  varies 
in  different  makes;  sometimes  it  is  uniformly  twisted 
throughought  its  length  and  again  it  may  be  made 
with,  what  is  termed,  an  increase  twist  to  give  greater 
strength  in  a  tong  drill.  Twist  drills  were  originally 
made  by  twisting  up  a  piece  of  flat  stock,  but  the 
present  method  of  manufacture  is  to  mill  the  helical 
grooves  from  a  round  bar  of  steel.  A  shank  is  pro- 
vided in  order  properly  to  hold  the  drill  and  drive 
it  through  the  work,  this  portion  being  either  straight 
or  tapering.  If  straight  it  may  be  h^ld  in  a  drill 
chuck  or  in  a  plain  bushing  with  set  screws,  but  if 
the  shank  tapers,  it  is  provided  with  a  flatened  end, 
or  *Hang,''  which  acts  as  a  driver  in  the  drill  socket. 
A  modern  twist  drill  has  a  slight  *'back  taper"  run- 
ning longitudinally  from  point  to  shank  so  that  it 
will  work  with  more  freedom.  Body  clearance  is  also 
provided  as  indicated  in  the  end  view  of  the  tool 
shown  in  the  illustration.  The  purpose  of  the  two 
clearances  is  to  avoid  the  heating  of  the  drill  by 


38 


fOOLS  AND  PATTERNS 


friction  in  the  hole  and  also  to  make  the  entting 
action  easier. 

The  cutting  angles  of  the  lip  of  the  drill  vary  from 
59  to  76  degrees  depending  on  the  material  which  is 
to  be  drilled;  ordinarily  a  drill  fof  »teel  and  iron  is 
ground  to  59  or  GO  degrees,  while  for  brass  the  angle 
may  be  around  75  degrees.  It  is  of  the  greatest  im- 
portance that  drill  angles  should  be  equal,  for  unless 
this  is  the  ease  the  hole  will  be  cut  too  large,  as 
indicated  at  P,  since  the  tool  is  working  aronnd  a 
false  center  which  is  not  the  actual  center  of  the 
drill  stock  itself.  In  such  a  case  the  longest  lip 
governs  the  size  of  the  hole,  as  may  be  readily  seen. 

Another  type  of  twist  drill,  G,  is  known  as  a  flat 
twist  drill.  As  made  by  some  manufacturers  it  has 
a  flat  shank  requiring  a  special  form  of  socket  for 
holding.  The  Pratt  &  Whitney  Co.  make  the  form 
illustrated  in  which  an  increase  of  twist  is  given  to 
the  shank  portion  to  provide  additional  surface 
which  is  ground  to  fit  the  taper  in  a  standard  socket, 
thus  doing  away  with  the  necessity  for  special  sock- 
ets. The  advantages  ckdmed  for  this  type  of  drill 
are  that  it  has  greater  chip  clearance  and  higher  pro- 
ductive capacity. 

Ckm  DriBs.— When  holes  are  to  be  drilled  in  cast 
iron  or  other  cast  metals  in  which  the  holes  have 
been  cored,  another  type  of  drill,  often  termed  a  "core 
drill,"  is  used.  Drills  of  this  kind,  H,  Figure  17,  are 
listed  by  manufacturers  as  "three-groove  chucking 
reamers."  It  may  be  noted  that  the  end  of  the  drill 
does  not  come  to  a  point,  as  in  the  case  of  the  regular 
twist  drill,  but  is  blunted  because  it  has  no  work  to 


BEIIiliING,  BOBING,  FOBaiNO 


do  at  the  center.  The  three  flutes  tend  to  keep  the 
tool  in  a  central  position  while  drilling.  Four  flutes 
instead  of  three  are  sometimes  used.  In  the  larger 
sizes  shell  drills,  K,  are  founc!  to  be  capable  of  very 
severe  service.  They  are  held  on  an  arbor  like  a  shell 
reamer  and  are  generally  four  fluted. 

An  important  point  in  connection  with  the  use  of 
core  drills  is  that  any  variation  or  eccentricity  of  the 
cored  portion  of  the  work  is  likely  to  affect  the  tool 
to  a  considerable  extent  so  that  the  resulting  hole  is 
not  true  with  the  remainder  of  the  work.  This 
trouble  can  be  easily  avoided  by  truing  up  the  hole 
for  a  short  distance  with  a  single-point  tool  before 
inserting  the  core  drill,  as  indicated  in  Figure  18. 

Counterbores.— When  a  shouldered  hole  is  to  be 
made,  such  as  that  shown  ii^  Figure  19,  the  counter- 
bore  is  generally  employed.  In  order  to  have  the  two 
holes  concentric,  two  methods  are  possible:  In  one  the 


we.  18,    STABTIHO  A  HOLE  WTTH  A  STARTINO  TOOL  PMOB 

TO  rm  VS9  OF  A  conE  pmM4 


1 


m 


AND  PATTBEMS 


BBIIiLma,  BOBINCJ,  FORCING 


41 


MG.  19.    VARIOUS  TYPES  OF  COXJNTERBORES 


work  is  revolved  and  the  cutting  tools  are  held 
rigidly  without  revolving;  the  holes  can  then  be  pro- 
duced by  two  or  more  cuts  of  the  tools  after  they  are 
set  out  to  the  required  diameters.  In  the  second 
method  the  work  is  stationary  and  the  tools  revolve; 
the  smaller  hole  is  usually  made  first  and  a  tool  called 
a  couiiterliorey  A,  like  that  shown  in  Figure  19,  hav- 
ing a  pilot,  B,  which  enters  the  smaller  hole,  does  the 
remainder  of  the  cutting  on  the  larger  diameter.  It 
will  be  noted  that  the  action  of  the  pilot  in  the  pre- 
viously drilled  small  hole  tends  to  steady  the  action 
of  the  counterbore  and  produce  a  concentric  hole. 

Several  varieties  of  connterbores  are  in  use,  the 
principles  of  which  are  the  same  as  that  shown  at 


A.  One  type,  D,  has  interchangeable  blades  or  cut- 
ting lips  and  removable  bushings,  C,  which  allow 
w(  rk  to  be  done  in  holes  of  various  diameters.  An- 
ot  ler  tjrpe,  E,  also  has  a  removable  pilot,  which  can 
be  provided  with  cutting  heads  of  different  diameters, 
but  the  pilot  does  not  revolve.  If  work  requiring  a 
high  degree  of  accuracy  is  intended,  the  type  with  a 
revolving  pilot  is  advisable.  Some  cases  occur  when 
it  may  be  possible  to  extend  a  pilot  somewhat  smaller 
than  the  hole,  so  that  it  can  be  guided  in  a  bushing 
beyond  the  work  itself.  In  either  of  these  cases  there 
is  little  danger  of  injury  to  the  finished  surface  of  the 
smaller  hole. 


wm.  20.  (a)  hahd  REiiifm  (b)  plain  vltwed  chucking 

(c)  mm  CHUCKIN0  reamer 


Beamers. — ^When  a  hole  is  to  be  accurately  finished 
to  a  given  diameter  it  may  either  be  bored  to  this 
size  by  successive  cuts  of  the  boring  tool  or  it  may 
be  reamed.  A  reamer,  therefore,  may  be  considered 
strictly  as  a  tool  for  sizing  a  hole.  Several  types  of 
reamers  are  in  common  use  and  the  selection  of  the 
type  for  any  particular  work  depends  upon  the  ma- 


42 


fOOLS  AND  PATTEBNS 


terial  to  be  eiit,  tie  diameter  of  the  work,  and  tbe 
preTions  operations  which  have  been  done  upon  it. 
As  reamers  are  used  entirely  as  finishing  tools,  the 
amount  of  metal  which  they  remove  ig  small  and  is 
dependent  upon  the  diameter  of  the  hole  and  the 
nature  of  the  metal. 

A  group  of  reamers  of  various  types  is  shown  in 
Figure  20;  while  the  types  here  represented  do  not 
inelmde  every  variety,  they  may  be  considered  as  rep- 
resentative. The  simplest  type  in  common  use  is  the 
plain  fluted  hand  reamer,  shown  at  A,  which  has  a 
squared  end  to  which  a  wrench  or  holder  can  be  ap- 
plied for  the  purpose  of  forcing  the  reamer  through 
the  hole.  Beamers  of  this  kind  are  sometimes  made 
with  spiral  flutes. 

The  plain  chucking  reamer,  B,  in  the  same  illus- 
tration,  is  largely  used  in  drill  press  or  turret  lathe 
work  and  is  made  with  either  a  taper  or  straight 
shank.  When  used  in  turret-lathe  work  it  is  held  in 
a  floating  holder,  different  types  of  which  are  de- 
scribed nnder  their  proper  heading.  The  type  of 
fluted  chucking  reamer  shown  at  B  may  have  the 
flutes  equally  spaced  around  the  periphery  of  the 
reamer  or  they  may  be  staggered  so  that  no  two  tooth 
spaeings  are  exactly  alike.  The  object  §f  this  ar- 
rangement is  to  prevent    chatter."  lii^^ 

Another  type,  called  a  rose  chucking  reamer,  C,  is 
intended  for  work  of  a  fragile  nature  or  for  thin 
work  which  might  be  distorted  in  reaming  with  an 
ordinary  coarse-fluted  reamer.  The  rose  reamer  has 
wider  lands"  (space  between  indentations)  and  is 
not  lipped  Eke  the  chneking  reamer  previously  men- 


DMLMNG,  BOBINO,  FOWIINO 


win.  21.    TTPES  OF  INSEBTED-BIiADE  REAMERS 

tioned.  It  should  cut  only  on  the  end,  and  the  ob- 
ject of  the  wide  lands  on  the  flutes  is  to  preserve  a 
bearing  surface  and  thus  tend  to  produce  greater  ac* 
curacy  in  the  work. 

Inserted-Blade  ReamCTS.— The  simplest  type  of  in- 
serted-blade  reamer  is  the  tool  shown  at  A  in  Figure 
21.  This  reamer  is  never  used  with  a  floating  holder, 
the  design  being  such  that  the  blade,  b,  floats  in  the 
holder,  a.  Fdr  certain  classes  of  work,  especially 
vertical  work,  as  on  a  vertical  boring  mill,  reamers 
of  this  type  may  be  made  to  do  excelliiiliprork. 
Upkeep  IS  provided  for  by  means  of  a  tapered 
screw  and  a  slot  in  the  blade  whereby  the  blade  may 
expanded  and  reground.  On  account  of  the  cost 
of  high-speed  steel  later  developments  in  the  de- 
sign  of  reamers  favor  the  inserted*blade  type  so  made 


TOOLS  AND  PATTERNS 


that  tlie  blades  can  be  removed  and  replaced  at  a 
nominal  expense.  By  this  means  tbe  upkeep  of  the 
tool  is  quite  low:  a  number  of  styles  can  be  purchased 
ill  the  Ameriean  market. 

A  good  example  is  tbat  shown  at  B  in  Figure  21, 
made  by  the  Pratt  &  Whitney  Co.  In  this  type  of 
reamer  the  body,  d,  is  provided  with  tapered  slots  in 
which  the  blades,  e,  fit.  The  clamps,  f,  in  the  sec- 
tional view,  lock  the  blades  by  means  of  the  screws 
shown.  Various  diameters  within  the  capacity  of  the 
reamer  can  be  readily  made  by  manipulating  the  lock- 
ing nnt  shown  at  g.  It  is  a  very  difficult  matter  to 
change  a  reamer  adjustment  of  this  kind  in  such  a 
way  that  all  the  blades  will  cut  equally,  but  it  is  a 
simple  matter  to  regrind  to  the  desired  size  after  set- 
ting the  blades  slightly  oversize  to  allow  for  the 
grinding. 

Another  excellent  type  of  inserted-blade  reamer 
is  shown  in  the  same  illustration  at  C.  In  this  type 
the  body  of  the  tool  is  cut  out,  as  indicated,  to  re 
ceive  the  blades,  h.  It  will  be  seen  that  these  blades 
are  so  made  that  each  forms  two  teeth,  and  are  held 
in  place  by  the  screws  shown.  When  a  reamer  of  this 
kind  becomes  worn  so  that  it  does  not  size  the  work 
properly,  the  blades  may  be  removed  and  strips  of 
paper  inserted  under  them,  after  which  they  can  h 
reground  to  the  desired  size. 

Twpat  Beamfin.— Before  reaming  a  tapering  hole, 
the  first  essential  i»  «iat  the  bored  hole  be  true  and 
straight.  When  the  taper  is  very  "shallow"— le., 
fhe  angle  of  the  taper  very  slight— a  single  reamer 
mtk  be  jmdf  as,  for  inatancei  in  making  a  taper  pi^ 


46 


©^FLUTED  8=  FLUTED 

ROUGHER  FINISHER 
NICKED  D  BREAK  CHIP  PLAIN  OR 

NICKED 


TAPER  SCRAPING 
TOOL  FOR  LARGE  WORK 


no.  22.    TYPES  OF  TAPER  REAMERS  / 

hole;  but  when  a  more  obtuse  angle  is  required  sev- 
eral tools  may  be  necessary  to  produce  the  final  taper. 
For  this  latter  work  the  first  two  reamers  may  be 
made  as  indicated,  in  Figure  22,  at  A  and  B.  In  the 
tool,  A,  the  flutes  are  cut  straight  but  are  threaded  or 
nicked  to  "break  the  chip"  and  make  the  cutting  ac- 
tion easier.  In  order  to  overcome  the  tendency  to- 
ward drawing  in,*'  a  slight  left-hand  spiral  may  be 
given  to  the  flutes,  the  angle  of  the  spiral  being  de- 
pendent somewhat  on  the  angularity  of  the  tapered 
hole.  It  is  also  advisable  m  some  cases  to  space  the 
teeth  unequally  to  avoid  chatter  which  is  more  likely 
to  occur  in  taper  than  in  straight  reaming.  Taper 
reamers  should  be  made  longer  than  the  holes  in 
which  they  are  to  be  used  in  order  to  provide  for  up- 
keep. Eoughing  reamers  should  have  fewer  flutes 
than  the  finishing  tool  for  greater  chip  clearance. 


TOOLS  AND  PATTEBNS 


Taper  reamers  are  occasionally  made  for  large 
work  with  a  single  inserted  blade,  such  as  that 
diowm  at  C  in  the  Ulustration:  A  tool  of  this  kind 
is  not,  strictly  speaking,  a  reamer,  bnt  is  more 
nearly  a  scraping  tool.  This  type  of  tool  is  vain, 
able  for  some  classes  of  work,  however,  as  it  can  he 
adjusted  to  size  very  readily  and  can  be  reground 
a  nnmb^  of  times. 


iror/r  .„ 

.A 

9 


mmm 


- 


IIO.  23.    SnfPLB  TTOBS  Of  BCWINQ  TOCKil 

Boring  Tools.— The  engine  lathe  is  generally  nsed 
when  a  hole  is  to  be  bored  in  but  one  piece  of  work 
wMch  can  be  revolved.  The  type  of  boring  tool  used 
for  small  holes  nnder  these  conditions  is  shown  ib 
Figure  23  at  A.  Due  to  its  construction,  a  tool  of 
this  kind  is  only  suited  to  very  light  work,  and  a 
number  of  cuts  must  be  taken  to  bring  the  work 
to  the  required  siae.  As  such  tools  are  seldom  used 
to  any  great  extent  in  manufacturing  work,  it  ^ 


mSlMm,  BORING,  FORGING  47 


unnecessary  to  mention  their  shortcomings.  They 
serve  the  purpose  for  which  they  are  intended — 
boring  holes  in  jigs  and  the  like,  and  therefore 
need  no  further  comment.  Tools  of  a  similar  char- 
acter but  somewhat  heavier  are  occasionally  used 
in  turret  lathe  work  for  boring  short  holes,  al- 
though a  boring  bar  is  generally  used  when  the 
size  of  the  hole  will  permit.  When  a  boring  tool 
of  this  type  must  be  used  for  manufacturing  work, 
it  is  better  to  make  it  in  the  form  shown  at  B  in 
the  illustration.  It  will  be  seen  that  this  tool  has 
a  more  substantial  nose  and  that  it  is  ground  to 
a  different  shape  than  the  toolmaker's  tool  shown  at 
A  in  the  illustration.  It  will  give  very  good  results 
on  short  work. 

When  a  turret  lathe  must  be  used  to  bore  a  hole 
and  the  size  of  the  hole  will  permit,  it  is  better  to 
use  a  bar  such  as  that  shown  at  A  in  Figure  24. 
Single-point  tools,  or  tools  having  but  one  cutting 
edge,  will  produce  more  accurate  work  than  multiple- 
cutting  tools,  although  they  will  not  turn  out  the 
work  as  rapidly.  The  bar,  B,  made  in  a  variety  of 
ways  to  suit  different  conditions,  is  used  in  many 
classes  of  work.  The  tool,  placed  straight  across  the 
bar,  is  held  with  a  set  screw  or  a  taper  pin,  and  may 
or  may  not  have  the  added  refinement  of  a  backing- 
up  screw  to  make  adjustment  easier.  The  bar  may 
»e  piloted  in  a  bushing  of  some  kind,  or  it  may  be  as 
shown  in  the  figure.  If  several  diameters  are  to  be 
machined  at  the  same  time  a  multiple  bar,  C,  can  be 
^ised  to  good  advantage,  the  general  points  in  con- 
isiruction  being  much  the  same. 


fOOI^  AND  FAvrnmB 


Flil-Oiitlir  Boring  Bin« — ^For  rapid  produeiion 
flat  cutters  are  frequently  used  in  bars  such  as  shown 
at  D,  Figuie  24.  The  advantage  obtained  by  the 
use  of  two  euttiiBg  edges  is  that  the  amount  of  work 
performed  by  each  cutter  is  less  than  with  a  single- 
point  tool,  and  therefore  the  feed  can  be  somewhat 
increased.  The  disadvantage  lies  in  the  fact  that 
diameter  mm  are  soon  lost  on  account  of  re-grind- 
ing, while  the  single  point  tool  can  be  re-set  to  a 
given  diameter  a  number  of  times  through  a  simple 
adjustment. 

For  very  heavy  cutting  a  cutter  head  is  made  up 
similar  to  that  shown  at  E  in  the  illustration.  In 
boring  automobile  cylinders,  or  other  work  of  similar 
character,  tools  of  this  kind  can  be  used  to  advan- 
tage, but  it  is  highly  important  to  have  all  the  cutting 
points  ground  to  the  same  diameter  and  angle  so  that 
they  will  do  an  equal  amount  of  work.  Bars  of  other 
varieties  besides  those  shown  are  used  in  general 
mannfaetnring,  but  the  working  principles  are  much 
the  same  as  the  ones  described. 

AdjnstaUa  Boring  Tool  for  Tool-Room  Work.— The 
requirements  of  the  toolmaker  are  somewhat  differ- 
ent from  the  requirements  in  the  manufacturing  de 
partments.  Therefore  the  type  of  boring  tool  which 
he  is  likely  to  favor  will  differ  from  those  previously 
described  and  may  take  the  form  of  that  shown  in 
Mgnre  25.  This  tool  will  probably  be  provided  with 
a  taper  shank,  A,  which  will  fit  the  tailstock  of  the 
lathe.  The  cutting  tool  itself  is  small  and  is  held  by 
two  screws,  as  shown,  in  the  swinging  block  pivoted 
at  B  in  the  body  of  the  toolhold^.  The  two  screws, 


DmiililKa,  dOMH€K  FOUeiMG  49 


wm.  24.  vABious  types  of  bobinq  babs 


TOOLS  AND  PATTERNS 


€/mck 


? 


m.  25.  TOoi*iiAKiaw^  apjo8tabub  bomnq  tool 

C,  C,  are  used  for  adjustment/  one  being  loosened 
and  the  opposite  one  tightened  until  the  desired 
diameter  is  obtained.  Other  varieties  of  this  tool 
may  be  found  in  any  manufacturers  tool  room.  A 
tooLaker  wiU  often  have  one  of  his  own  make 
which  is  of  course  superior  to  all  others."  For 
boring  bushing  holes  in  jigs,  tools  of  this  sort  are 
almost  indispensaUe. 

Recessing  Tools.— In  turret  lathe  work  it  is  often 
necessary  to  produce  a  recess  or  groove  in  the  in- 
side of  the  work.  When  the  work  is  of  medium 
size,  so  that  a  good-«ized  tool  can  be  used,  no  par- 
ticular difficulty  is  experienced,  for  the  work  can  be 
done  by  a  number  of  different  methods.  If  the  work 
is  done  on  an  engine  lathe,  a  tool  may  be  conven- 
iently held  on  the  cross  slide  of  the  lathe,  as*  indi- 
cated at  A,  Figure  26,  and  the  carriage  can  be  with- 
drawn until  the  tool  has  reached  the  proper  depth, 
after  which  it  can  be  fed  along  the  distance  re- 


DEILLING,  BORING,  FORGING  51 


MO.  26.    A  SIMPLE  REGESSINO  TOOL  ON  AN  ENGINE  LATHE 

quired  to  produce  the  work,  as  shown  at  B.  It  must 
be  remembered,  however,  that  many  varieties  of  tur- 
ret lathes  do  not  have  a  cross-sliding  movement  to 
the  turret,  nor  does  the  cross  slide  in  some  other 
varieties  have  a  longitudinal  power  feed.  Hence,  it 
is  necessary  to  design  a  recessing  tool  in  such  a 
way  that  it  will  be  self-contained  and  have  its  own 
moving  parts,  irrespective  of  the  turret  movement. 

Much  depends  upon  the  naturo  of  the  groove  to 
be  cut  If  it  is  narrow,  such  as  that  shown  in  Fig- 
ure 27,  it  is  easily  possible  to  build  a  tool  of  a  very 
simple  character  to  be  operated  by  the  wojkman. 
In  this  ease  the  tool  consists  simply  of  a  body,  A, 
in  which  the  holder,  B,  is  set  eccentrically  to  the 
center  line  of  the  spindle  and  at  a  sufficient  distance 
to  give  the  depth  of  cut  desired.  The  handle,  C, 
hirnishes  the  necessary  feed. 

When  a  recess  is  cut  deeply  into  the  work,  and 


m 


TOOLS  AND  PATT£BNS 


wm.  2B.  mammm  tool  wm  Tumm  mths 


DBIIililNG,  BOBINO,  FOBaiNG  53 


when  the  tool  extends  a  considerable  distance  from 
the  turret  face,  a  scheme  snch  as  that  indicated  in 
Figure  28  can  be  utilized  to  good  advantage.  In 
this  case  the  body  of  the  tool,  A,  is  mounted  on  the 
turret  and  contains  a  sliding  member,  B,  in  which 
is  mounted  the  recessing  bar,  C,  having  a  tool  at 
Assuming  that  there  are  tools  on  the  front 
of  the  cross  side,  which  are  used  in  connection  with 
the  work,  and  that  the  rear  of  the  slide  is  supplied 
with  a  support,  E,  by  means  of  which  the  recessing 
bar  is  supported  and  fed  into  the  work  by  with- 
drawal of  the  cross  slide;  it  will  be  seen,  then,  that 
a  movement  of  the  slide  will  carry  the  tool  into  the 
work  as  deeply  as  permitted  by  the  stop  screw,  F. 
The  slide  carrying  the  recessing  bar  is  controlled  by 
a  spring,  so  that  when  the  feeding  pressure  is  re- 
leased the  spring  wiU  return  the  sMe  to  its  normal 
position. 

Extraordinary  cases  occur  occasionally  in  ma- 
chine shop  practice  when  a  number  of  parts  must  be 
made  which  call  for  more  elaborate  tooling  than  is 
ordinarily  required.  An  example  of  this  sort  is 
shown  in  Figure  29.  In  this  case,  the  work,  A,  is 
a  steel  casing  with  two  recesses  equidistant  from  the 
center  line  as  shown  at  B.  The  work  is  of  large  size 
and  requires  a  20-inch  swing  turret  lathe  to  handle 
it.  It  will  be  seen  that  the  two  recesses  are  in  such 
positions  that  they  can  not  readily  be  machined.  As 
a  support  for  any  tool  making  this  cut  is  necessary,  a 
bushing  has  been  inserted  in  the  fixture  to  hold  the 
piece  so  that  a  pilot  can  be  used  on  the  bar  for  re- 
cessing.  This  bar  has  been  drilled  to  receive  a  rod, 


TOOLS  AND  PATTERNS 


Wm,  29.    IM  XLAB0R4TB  KBCE8BEK0  VOC«<  FOR  A  LABOB 


STEEL  CASINQ 

C,  on  which  two  angular  splines  have  been  cut.  The 
splines  engage  with  the  two  small  tool  blocks,  D, 
which  hold  the  recessing  tools.  The  mechanism  is 
operated  by  means  of  a  pinion,  E,  which  engages 
with  a  rack  cut  on  the  operating  bar,  as  clearly  indi- 
cated in  the  Ulnstration. 

It  is  obvious  that  any  tool  of  this  kind  would  not 
be  built  unless  very  many  pieces  were  to  be  ma- 
chined, as  it  would  not  prove  economical  otherwise 
because  of  the  high  first  cost.  For  the  work  shown, 
however,  some  thousands  of  pieces  were  to  be  made, 
and  the  elaborate  equipment  paid  for  itself  many  times 
over  in  the  saving  of  time  and  in  the  accuracy  of  pro- 
duction. As  the  depth  of  the  recess  on  this  piece  was 
rather  important,  it  was  essential  that  the  spacing  of 
the  grooves  should  be  symmetrical  about  the  center 
line,  which  also  made  the  tool  so  much  more  essential 


CHAPTER  IV 


TURNING,  FORMING,  AND  THREADING 

Hollow  Mills.— In  roughing-down  bar  stock  similar 
to  the  piece  shown  at  A  in  Figure  .30,  a  hollow  mill  is 
frequently  used,  but  this  type  of  tool  is  not  to  be 
recommended  for  accuracy.  But  as  it  has  several 
cutting  lips  it  will  remove  stock  rapidly  and  can  be 
used  for  roughing  operations  to  good  advantage. 
The  ring:,  B,  is  used  to  prevent  the  lips  of  the  tool 
from  springing  and  also  to  make  small  adjustments 
by  drawinig  in  the  lips  to  a  slightly  smaller  diameter 
when  necessary,  but  the  adjustment  obtainable  on 
this  type  of  hollow  mill  amounts  to  only  a  few  thou- 
sandths of  an  inch.  An  adjustable  type  such  as  shown 
at  C,  is  much  more  expensive  but  possesses  some  ad- 
vantages. The  cutting  tools,  D,  D,  are  of  the  in- 
serted type  and  are  controlled  as  to  their  diameter  by 
a  ring  with  cams  cut  upon  it  which  engage  with  the 
cutting  tools  and  force  them  in  or  out  as  desired. 
Although  a  tool  of  this  type  can  be  more  accurately 
adjusted  to  a  given  diameter  than  the  one  previously 
described,  it  will  not  remove  stock  in  as  great  a 
quantity  nor  has  it  the  desirable  features  of  chip 
clearance  that  the  former  tool  possesses. 

Another  type  of  hollow  mill  designed  for  excep- 
tionally heavy  cutting  and  large  stock  reduction  is 

55 


It 


IHIOIiS  AND  PATTfiRNB 


m.  90.  wKmtuosTiFmmmoiAmruaiM 
sliown  at  E.  This  tool  is  of  special  character  and  is 
designed  for  a  single  purpose.  It  will  be  noticed, 
however,  thallMII^  tools,  are  adjustable  and 
that  they  are  heavy  in  section  so  as  to  carry  away 
heat  rapidly.  Tools  of  this  sort  are  designed  only 
for  fhe  mmt  severe  service  and  are  not  economiea) 


TURNING,  FORMING,  THREADING 


57 


unless  stock  reductions  are  large  and  a  great  number 
of  pieces  of  the  same  character  are  to  be  machined. 
An  important  point  in  connection  with  all  hollow 
mills  is  the  back  clearance  which,  on  the  type  shown 
at  A  should  be  at  least  an  eighth  of  an  inch  to  the 
foot.  The  cutting  edges  of  hollow  mills  should  be  a 
trifle  ahead  of  the  center  for  steel  work  but  on  center 
for  brass. 

Turning  Tools. — On  turret  lathe  work  tools  used 
for  turning  are  made  up  in  a  different  way  from 
those  employed  on  the  engine  lathe.  On  the  engine 
lathe  the  tools  are  held  on  the  cross  slide  of  the  ma- 
chine in  suitably  designed  tool  holders,  while  in  tur- 
ret lathe  work  the  holders  are  mounted  on  the  turret 
and  the  tools  are  held  either  horizontally  or  ver- 
tically. One  of  the  simplest  types  of  turning  tool  is 
shown  in  Figure  31,  the  holders  in  this  case  being 


31.  A  smPLB  wmatme  tool  wm  TumciBT  lathe  wokk 


58  fOOIiS  AND  PATTERNS 

made  of  easi  iron  and  bolted  to  the  turret  face.  The 
tool  is  set  at  an  angle  and  is  held  in  place  by  two  set 
screws.  Adjustments  for  diameters  can  be  readily 
made  within  the  capacity  of  the  tool.  For  short 
lengths  and  snlall  diameters,  a  tool  of  this  kind  will 
give  excellent  results;  but  when  the  work  is  long,  as 
in  the  turning  of  bar  work  on  a  screw  machine,  it  is 
necessary  to  provide  support  for  the  work  opposite  to 
the  eutting  point  of  the  tool. 

A  simple  type  of  tool  for  this  latter  purpose,  usu- 
ally termed  '*box  tool'',  is  shown  in  Figure  32.  The 


110.  32.    A  SIMPLE  BOX  TOOL  FOR  TURRET  LATHE  WORK 


tool  is  mounted  in  a  block  opposite  to  which  a  V- 
shaped  supporting  block  is  so  placed  that  it  can  be 
adjusted  to  the  diameter  of  the  work  being  cut. 
M ttkers  of  turret  lathes  have  developed  a  great  va- 
riety of  tools  along  these  lines  to  suit  the  particular 
machine  which  they  manufacture.  For  small  screw- 
maehine  work,  box  tools  with  two  or  more  adjustable 
blocks  are  frequently  made  which  are  extremely  use- 
ful for  automatic  and  light  hand-screw  machine  work. 

Adjustable  Turning  Tools. — ^For  bar  work  it  is  very 
desirable  to  have  tools  which  can  be  adjusted  rapidly 


TUBNING,  FORMING,  THREADING  m 


wo.  33.   ADJUSTABLE  TURNING  TOOL  WITH  ROLLER  BACK  RBSTB 

Pratt  &  Whitney  Co. 

to  various  diameters  within  their  capacity,  and  on 
turret  lathe  work  several  fools  of  the  styles  shown 
in  Figure  33  may  be  mounted  on  the  turret  and  con- 
trol several  diameters  on  the  bar.    Such  tools  are 
made  with  both  roller-back  and  V-back  rests,  the 
back  rests  being  adjustably  mounted  so  that  they  can 
be  used  either  for  following  or  leading.   When  used 
as  following  back  rests,  they  are  set  to  the  diameter 
at  which  the  tool  is  at  work  and  sUghtly  behind  a 
pomt  opposite  the  cutting  tool.   When  used  as  lead- 
ing back  rests,  the  material  must  either  be  bright 
mm  steel  or  it  must  have  been  finished  to  a  given 
^immeter  m  a  previous  operation.  Leading  back  rests 
can  never.be  ised  on  rough  stock;  but  following  back 
rests,  as  they  work  directly  behind  a  surface  which 
jas  just  been  finished,  are  always  used  in  rough 
»?ock  turning.  The  dilference  between  the  use  of  the 


60 


TOOLS  AND  PATTERNS 


V-back  rest  and  tlie  roller-back  rest  is  that  the  rollers 
are  less  likelv  to  mar  the  work,  while  V-back  rests 
mav  cause  sUght  abrasions,  especially  if  work  i»  done 
at  high  speed.  However,  on  automatic  work  of  small 
diameter  the  V-rests  are  commonly  used  with  per- 
fectly satisfactory  result.  - 

Open-side  Turning  Tools.— The  tool  shown  m  Fig- 
ure 34  is  used  for  turning  short  lengths  when  the 


no.  34.    OPEN  SIDE  TURNING  TOIM^ 
Pratt  ft  Whitney  CJo. 

work  is  held  rigidly;  therefore  it  does  not  require 
back  rest  support,  A  tool  of  this  nature  is  adjustable 
to  different  diameters  within  its  capadty,  and  some- 
times possesses  an  added  refinement  in  an  adjustable 
stop  or  an  index  on  the  screw  so  that  it  can  be  set 
for  different  diameters  for  both  roughing  and  finish 
ing  cuts. 

Overhead  Turning  Tools.— It  is  important  that  any 
type  of  turning  tool  should  be  held  rigidly  to  avoid 


TUBNING,  FOBMINa,  THREADING  61 


FIG.  35.   SPECIAL  PILOTED  TURNINO  TOOL  imRAPn)  PRODUCTION 


the  chatter  resulting  from  excessive  vibration.  For 
this  reason  turret  lathe  tools  for  heavy  classes  of 
work--such  as  castings,  forgings,  and  the  like— 
should  be  so  constructed  that  they  will  have  ample 
section  to  withstand  cutting  strains  without  spring- 
ing away  from  the  work.  For  manufacturing  work 
in  large  quantities,  special  tools  are  frequently  built 
sttch  as  that  shown  in  Figure  35  at  A.  It  will  be  seen 
that  this  tool  is  mounted  on  the  turret  of  the  turret 


62 


TOOLS  AND  PATTERNS 


lathe  and  has  additional  support  from  the  pilot  bar, 
B,  which  enters  a  bushing  in  a  bracket  on  the  head 
stoek  of  the  machine.  The  several  tools  are  remov- 
able  and  adjustable,  so  that  they  can  be  repW  and 
regronnd  when  necessary.  Such  tools  are  not  in- 
tended for  universal  use  but  are  specially  designed  to 
meet  the  requirements  of  a  particular  case.  It  is  al- 
ways advisable,  in  making  up  a  tool  of  this  kind, 
however,  to  provide  as  much  latitude  as  possible,  so 
that  in  the  event  of  a  change  in  design  the  tool  can 
still  be  used  with  slight  modifications. 

Tuniiii;  Tools  for  Vorfeieal  Boring  Mills.— Many 
people  do  not  consider  that  the  vertical  boring  mill  is 
sufficiently  adaptable  to  handle  special  classes  of 
manufacturing  work  to  good  advantage,  but  its 
power  and  stability  are  such  that,  if  properly  tooled, 
it  will  prove  a  valuable  manufacturing  machinel  The 
majority  of  boring  mills  in  use  throughout  the  coun- 
try are  not  run  anywhere  near  to  their  maximum  effi- 
ciency. Only  a  short  time  ago,  while  investigating 
conditions  in  an  old  factory,  I  discovered  three  bor- 
ing mills  at  work  continuously,  yet  only  turning 
out  about  one-fifth  of  the  product  which  they  shpuld 
liave  accomplished.  When  the  Superintendent  was 
asked  why  these  machines  seemed  to  be  such  small 
producers,  he  informed  me  that  they  turned  the  work 
out  ''as  fast  as  the  assembling  room  could  use  it," 
so  lie  had  no  fault  to  find. 

The  multiple  turning  tool  head  shown  in  Figure 
36  gives  an  idea  of  the  adaptability  of  multiple  tools 
to  a  vertical  boring  mill  when  the  product  is  suffi 
ciently  large  to  warrant  a  little  expenditure  for  tools. 


TUBNING,  FOBMING,  THBBADINQ 


63 


KG.36.   SFWJIAL  TORNmo  TOCM  OH  A  VERTICAL  WmiNG  MILL 


In  this  ease  the  heavy  tool  holder,  A,  contains  three 
tools,  B,  C,  and  D,  which  all  work  simultaneously  on 
the  casting.  At  the  same  time  the  two  tools,  E,  and 
* ,  m  the  left-hand  head  are  at  work  facing  the  sur- 
taees  indicated.  It  is  unnecessary  to  go  into  the  mat- 
ter of  turning  tools  on  the  vertical  boring  mill  to  any 
great  extent  as  the  more  modem  machines  used  in 
mamifaeturing  are  provided  with  a  side  head  in  ad- 
^on  to  a  turret,  each  containing  a  number  of  tools. 
When  a  machine  of  this  type  is  used,  the  side  head 
provides  a  means  of  setting  up  four  or  more  tool's  to 
hp  °P*''"ate^  in  sequence,  and  adjustment  of  the  side 
leaa  permits  diameter  settings  to  be  easily  made. 


M 


TOOLS  AND  PATTEBNS 


tMtiMg-M  TodhL—The  ordiBary  type  of  tool  used 
for  cutting  off  work  which  has  been  previously  turned 
or  formed  is  shown  in  Figure  37  at  A.  Such  tools, 
however,  are  uneconomical,  for  after  grinding  a  few 
times,  they  must  be  annealed  and  ref orged,  or  drawn 
out  to  their  former  length.  The  inserted-blade  type 


wm.  37.  TYPES  or  cwraNQ-ow  togim 

of  cutting-off  tool,  shown  at  B  in  the  same  illustra- 
tion, is  much  more  economical,  for  it  is  so  designed 
that  the  blade,  C,  can  be  clamped  securely  in  the 
holder  and  adjusted  to  any  desired  position  without 
difficulty.  The  holder  is  so  made  that  it  will  fit  sev- 
eral different  sizes  of  tool  posts,  thereby  making  its 
adaptability  to  different  classes  of  work  and  different 
machines  so  mueh  the  greater.  In  the  holder  showB, 
the  Tblades  can  be  bought  ready-made  to  slip  into  the 
holders,  and  only  require  an  occasional  grinding  to 
keep  them  in  condition. 


TURNINa  FOBMING,  THREADING  65 


Threading  Tools.— The  simplest  form  of  threading 
tools  is  the  forged  tool  shown  at  A  in  Figure  38, 
Such  a  tool  is  used  for  plain  threading  on  the  engine 
lathe  and  needs  no  particular  comment  as  the  nature 
of  the  operation  is  so  well  known.  In  any  threading 


Work 

A 

A"' 

wm,  38.    THE  SIMPLEST  WORM.  OF  THREADING  TOOL 


tool  there  are  two  essential  points;  first  the  correct 
shape  of  the  tool  itself,  and  second,  its  setting  in  re- 
lation to  the  work.  K  a  threading  tool  is  ground  to 
the  correct  angle  on  its  sides  and  is  set  on  the  center 
of  the  work,  it  should  produce  a  threaded  form  of  the 
correct  angle.  If,  however,  it  does  not  come  into 
contact  with  the  work  at  the  proper  point,  and  if  the 
cutting  face  is  tipped  one  way  or  the  other  to  bring 
the  point  on  center,  the  resulting  angle  of  thread  will 
not  be  correct. 

Because  of  these  facts,  it  is  evident  that  the  great- 
est care  must  be  exercised  both  in  grinding  and  in 
setting  any  sort  of  threading  tool.  In  turret  lathe 
^vork,  threading  tools  of  the  single-point  variety  can 
^ot  be  used  unless  the  machine  is  provided  with  a 


66 


TOOLS  AND  PATTEBNS 


thread-chasing  attachment  whereby  the  lead  of  the 
screw  can  be  properly  controlled.  There  are  many 
eases,  however,  when  such  an  attachment  is  a  great 
advantage,  and  it  is  in  cases  of  this  kind  that  a  spe 
cial  design  of  entting  tool  is  desirable.  When  the 
thread-chasing  attachment  is  applied  to  the  cross 
slide  of  the  machine,  an  ordinary  type  of  tool  may 
be  used  for  the  work  if  desired;  but  when  the  thread- 
ing attachment  afleets  the  turret  slide,  another  type 
of  tool  may  be  found  necessary. 

If  the  work  calls  for  an  interior  thread,  a  bar,  such 
as  that  shown  at  A  in  Figure  39,  can  be  used  with 
a  tool  of  the  single-point  type,  as  B,  or  of  the  chaser 


110.  39.    TYPES  or  THREAD  OHASIMO  TOOUI 


TURNING,  FORMING,  THREADING 


67 


type,  as  C.  This  bar  must  be  held  in  a  special 
holder  on  the  turret,  which  provides  for  quick  with- 
drawal  and  a  micrometer  stop  for  depth.  A  tool  slide 
of  this  sort  can  be  easily  applied  to  the  turret  of  the 
machine  and  presents  no  great  difficulty  in  the  mat- 
ter of  design.  When  the  turret  itself  has  cross-slid- 
ing features  and  a  micrometer  dial  adjustment,  there 
is  no  necessity  for  an  extra  tool  holder  of  the  type 
mentioned. 

Goose  Nedc  Threading  Tool— Due  to  the  peculiar 
construction  of  a  threading  tool  it  is  very  likely  to 
chatter  under  the  cut.  As  chatter  is  caused  by  a 
rapidly  repeated  springing  away  of  the  tool  from  the 
work  and  by  an  equally  repeated  digging  in  again, 
both  tool  and  work  should  be  held  so  rigidly  that 
such  vibration  will  not  be  possible.  Such  a  condition 
is  difficult  to  obtain,  however,  and  therefore  the  tool 
may  be  so  constructed  that  it  will  never  have  a 
tendency  to  dig  in.  A  special  tool  of  this  nature, 
made  especially  for  threading  work  on  the  turret 


Wdrk 


Turrwf 
 ^ 

^Q.  40,    A  GOOSE-NECK  THREADING  TOOL  FOR  TURRET  I4ATHE 


68 


TOOLS  AND  PATTERNS 


lathe,  is  shown  in  Figure  40.  The  tool-holder  body 
18  mounted  on  the  bar.  A,  which  is  held  in  the  tur- 
ret of  the  machine.  The  body  is  drilled  at  B  and 
slotted  at  C  to  allow  for  springing  action.  The 
threading  tool,  D,  is  locked  in  position  and  is  ground 
to  the  correct  angle  for  threading.  In  use,  the  posi- 
tion of  the  spring  hinge  allows  the  tool  to  spring 
away  from  the  work  without  digging  in. 

Forming  Tools.— When  it  becomes  necessary  to 
machine  a  form  a  number  of  more  or  less  irregular 
shapes  on  an  engine  lathe,  turret  lathe,  or  other  ma- 
chine of  similar  character,  a  forming  tool  of  some 
sort  is  indispensible.  When  only  a  single  piece  is  to 
be  made,  the  operator  can  work  out  the  shape  a  little 
at  a  time  on  an  engine  lathe  to  fit  a  templet  of  sheet 
steel  which  has  been  carefully  laid  out  to  the  re- 
quired dimensions. 

There  are  many  kinds  of  forming  tools  whose  utility 
depends  to  a  great  extent  on  the  class  of  work  for 
which  thev  are  intended,  as  well  as  the  number  of 
pieces  which  are  to  be  machined  and  the  accuracy 
required  in  the  finished  product.  The  type  of  tool 
selected  for  any  given  piece  of  work,  therefore,  should 
be  determined  by  these  factors.  For  example,  in  the 
work  shown  at  the  upper  part  of  Figure  41,  a  simple 
angular  groove  is  to  be  cut  on  a  lot  of  500  pieces. 
It  would  be  inadvisable,  therefore,  to  go  to  any  great 
expense  in  the  matter  of  a  forming  tool.  A  rect- 
angular tool.  A,  of  some  standard  section  should  be 
formed  to  the  shape  shown  at  B  with  very  little  ex- 
pense or  trouble,  and  the  work  may  be  produced 
without  difficulty.    If  such  a  tool  as  this,  however, 


TUKNING,  FOBMINO,  THRSADINe 


TO.  41.   THBES  TYPES  OF  SIMPLS  FOElflNa  T0(»£ 


70 


TOOL»  AND  PATTERNS 


were  to  be  used  day  after  day  and  week  after  week, 
it  would  not  give  good  results.  Freqnent  regrinding 
would  change  the  shape  and  size  so  that  it  would 
soon  need  to  be  .replaced  by  another.    This  is  due 
to  the  fact  that  the  clearance  as  indicated  by  the 
dotted  line  is  increasingly  smaller  than  the  part  of 
the  tool  doing  the  cutting,  so  that  as  the  face  is 
ground  away  the  tool  becomes  narrower  and  does 
not  cut  a  groove  of  the  desired  width.    To  avoid 
changes  in  form  caused  by  regrinding,  an  angularly 
set  forming  tool,  such  as  that  shown  at  C  in  the 
center  of  Figure  41  can  be  used  to  advantage.  In 
this  case  a  holder  F,  of  special  form  is  provided 
on  the  cross  slide  of  the  machine,  bolted  down  in 
some  approved  manner  according  to  the  form  of  slide 
on  which  it  is  used.    The  holder  is  dovetailed  at 
E  to  receive  the  forming  tool  on  which  the  correct 
form,  C,  has  been  fashioned.  The  design  of  the  tool 
is  such  that  when  it  is  ground  flat  across  the  front 
it  will  produce  the  required  form.  Clearance  is  taken 
care  of  by  the  angle  at  which  the  tool  is  set  in  the 
holder.  Suitable  clamping  screws  are  provided  in  the 
holder  so  that  as  re-grinding  is  done  adjustment  can 
be  made  to  keep  the  cutting  edge  always  at  the  center 
Ine.  In  a  tool  of  this  character,  which  is  required 
for  very  wide  forms  and  heavy  cutting,  a  set  screw 
is  sometimes  placed  in  the  holder  directly  under  the 
tool  to  provide  a  firm  support  and  take  the  thrust 
of  the  cut.    When  such  provision  is  not  made  it 
may  be  found  necessary  to  "shim*'  up  the  tool  to 
prevent  it  from  pushing  down  under  the  pressure  of 
the  cut.    Tools  of  this  kind  are  largely  used  on 


TURNING,  FORMING,  THREADING  71 


turret  lathe  and  screw  machine  work  for  producing 
various  form  and  shapes  up  to  four  or  five  inches 

in  length. 

Smaller  work,  such  as  that  on  automatic  and 
small  hand-screw  machines  can  be  handled  to  ad- 
vantage with  the  circular  type  of  forming  tool,  H, 
shown  in  the  lower  part  of  Figure  41.    This  type 
is  tapped  out  to  receive  a  screw  which  passes 
through  a  special  tool  holder  on  the  cross  slide  of 
the  machine.   If  the  holder  is  made  for  the  rear  of 
the  cross  slide,  the  center  line  of  the  screw,  K,  is 
from  i/g-  to  14-inch  below  the  center  of  the  work. 
Wlien  the  holder  is  designed  to  be  used  on  the  front 
of  the  cross  slide,  the  center  is  about  an  equal 
amount  above  the  work  center,  as  indicated  in  the 
illustration.   This  arrangement  is  for  the  purpose  of 
giving  a  greater  clearance  to  the  tool.    It  will  be 
seen  that  a  tool  of  this  sort  can  be  ground  a  great 
number  of  times  and  still  preserve  its  form.  Further- 
more, it  is  a  type  not  difficult  to  make,  as  it  can  be 
turned  on  an  engine  lathe  to  the  desired  form  and 
then  cut  out,  as  at  M,  to  give  the  cutting  lip.  Since 
the  cutting  edge  of  the  tool  is  not  on  the  center  on 
which  the  turning  of  the  tool  is  accomplished,  a 
suitable  allowance  for  this  difference  must  be  made 
when  shaping  it.    Formulas  for  this  type  of  tool 
can  be  found  in   Machinery's  Handbook." 


MILLING  AND  PLANING 

Milliinf  PiwefMl. — The  process  of  milling  a  sur- 
face or  form  consists,  essentiaUy,  in  holding  the 
work  to  be  milled  firmly  and  pushing  it  against 
a  revolving  cutter  which  removes  the  stock  at  a 
very  rapid  rate.    The  cutter  is  held  in  some  ap- 
proved manner  in  the  spindle  of  a  milling  machine, 
or  on  an  arbor,  either  in  a  vertical  or  horizontal 
position  depending  upon  the  nature  of  the  work 
and  the  type  of  machine  to  which  it  is  applied. 
Milling  machines  are  of  several  fundamental  types, 
each  possessing  features  more  or  less  distinctive 
according  to  the  manufacturer  and  the  particular 
class  of  work  for  which  the  machine  is  intended. 
Thus  we  have  hand  milling  machines,  plain  miHing 
machines,  the  Lincoln  type  of  milling  machines,  uni- 
versal milling  machines,  and  so  on,  all  of  which  are 
built  with  a  horizontal  spindle.    Then  there  are 
vertical,  rotary  table,  multiple  spindle,  duplex,  and 
continuous  milling  machines,  some  of  which  have 
vertical  spindles  while  others  have  horizontal  spin- 
dles or  even  a  combination  of  horizontal  and  verti 
cal  spindles  on  the  same  machine.    In  fact,  the 
ramifications  in  these  machines  are  somewhat  diffi- 
cult to  keep  in  touch  with  from  day  to  day  on  ac- 


73 


count  of  the  many  developments  in  rapid  produc- 
tion processes. 

Factors  Influencing  Machine  Selection.— When 
any  piece  of  work  is  to  be  machined  by  milling 
processes  the  proper  machine  to  produce  it  most  eco- 
nomically must  first  be  determined.  Next,  having  de- 
termined the  machine  to  use,  the  method  of  holding 
the  work  must  be  considered  and  a  fixture  designed 
for  it;  finally  the  type  of  cutter  to  be  used  must  be 
decided  upon.  Several  factors  have  an  influence  on 
these  points  and  are  of  great  importance.  They  in- 
clude: 

1.  Nature  and  composition  of  the  material  to  be 
cut. 

2.  Size  of  the  work. 

3.  Amount  of  metal  to  be  removed. 

4.  Accuracy  required. 

5.  Width  and  shape  of  cut. 

6.  Number  of  pieces  to  be  machined. 

It  is  obvious  in  considering  the  nature  and  com- 
position of  the  material  to  be  cut  that  for  instance, 
a  heavy  piece  of  alloy  steel  would  require  a  powerful 
machine  in  order  to  remove  the  stock  to  the  best 
advantage,  while  a  light  piece  of  aluminum  or  brass 
could  be  handled  more  economically  on  a  hand-feed 
or  plain  machine. 

The  size  of  the  work  also  has  an  effect  on  the  ma- 
chme  to  be  used,  for  it  not  infrequently  happens 
™t  a  light  piece  of  work  of  large  size  must  be 
?nachined  on  a  heavy  machine  solely  on  account  of 
the  range  required.    In  machining  heavy  forgings 


74 


TOOLS  AND  PATTERNS 


©f  alloy  steel,  miUiiig  machines  of  great  power  must 
be  used,  and  the  fixtnres  in  which  the  work  is  held 
must  be  of  the  most  massive  design  in  order  to  hold 
the  work  securely  and  prevent  vibration  or  chatter. 

The  amonnt  of  metal  to  be  removed  affects  the 
selection  of  the  machine  tool  on  account  of  the 
power  needed  to  pull  the  cut.  At  the  same  time 
it  influences  the  design  and  form  of  the  milling  cutter 
adapted  to  the  work. 

Speaking  generally,  surfacing  cnts  on  castings  are 
best  handled  by  a  face  mill  or  end-milling  cutter  ar- 
ranged to  cut  either  horizontally  along  the  side  of 
the  work,  if  used  on  a  horizontal  milling  machine,  or 
vertically  on  top  of  the  work  if  used  on  a  vertical- 
spindle  machine.  Steel  work,  on  the  contrary,  can 
more  profitably  be  handled  with  a  spiral  milling 
cutti»r,  the  cut  being  taken  in  a  direction  parallel 
with  the  center  line  of  tkiil^  of  rotation.  The 
accuracy  with  which  a  piece  of  work  must  be  finished 
determines  whether  a  single  roughing  cut  will  be  suffi- 
cient or  whether  both  roughing  and  finishing  cuts  must 
be  taken.  For  the  general  run  of  work  which  does  not 
require  a  high  degree  of  accuracy,  a  single  cut  may  Im 
taken  with  success,  but  when  interchangeable  work 
within  close  limits  of  accuracy  is  to  be  manufactured 
it  is  usually  advisable  to  take  two  cuts. 

The  width  and  shape  of  the  cut  determine  both  the 
class  of  machine  to  be  used,  the  kind  of  cutters  neces- 
sary, and  the  fixti^re  required.  In  modern  practice,  a 
milling  machine  having  both  vertical  and  horizontal 
spindles  is  often  selected  for  a  piece  of  work  of  larg« 
size  and  the  fixtures  are  designed  so  that  several  pieces 


MILLING  AND  PLANING 


75 


may  be  machined  simultaneously.  There  are  machines 
on  the  American  market  today  having  as  many  as 
seven  spindles,  all  of  which  may  be  working  simul- 
taneously  on  a  certain  piece  of  work.  Furthermore, 
the  work  may  be  roughed  and  finished  iij  the  same 
machine,  one  **bank''  of  cutters  serving  for  the  rough- 
ing cuts  and  the  others  for  the  finishing  operations. 
Obviously,  machines  of  this  character  are  very  expen- 
sive, but  for  high  production  work  they  are  great 
money  savers.  Here  it  will  be  seen  that  the  number 
of  pieces  to  be  machined  is  an  important  factor  in 
regard  to  the  type  of  machine  used.  Another  point 
in  this  connection  which  should  not  be  overlooked  is 
the  type  of  fixture  which  is  used,  but— this  matter 
will  be  dealt  with  in  greater  detail  under  a  later  head- 
ing. 

Milling  Cutters.— The  milling  cutter.  A,  Figure  42, 
IS  an  end  mill  of  the  ordinary  variety  with  straight 
flutes.  This  type  of  cutter  can  be  used  for  milling 
the  edges  of  a  surface  on  either  a  vertical  or  hori- 
zontal machine,  and  is  provided  with  a  taper  shank 
to  fit  the  milling  machine  spindle.  The  form,  B,  is 
of  the  center-cut  type.  It  can  be  fed  directly  into  the 
work  if  necessary,  the  teeth  being  so  cut  on  the  end 
as  to  permit  this.    With  the  type  A,  the  form  of 

tooth  on  the  end  does  not  permit  such  a  cut  to  be 
taken. 

The  cutter,  C,  is  an  end  mill  of  the  same  general 
type  as  that  shown  at  A,  except  that  the  flutes  are 
cm  spirally.  The  cutting  action  on  the  side  of  this 
J^ill  is  better  than  that  on  the  straight  fluted  mill,  A, 
because  the  entire  width  of  the  flute  is  not  all  in 


76 


TOOLS  AND  PATTBKNS 


FIG.  42.    GROUP  OP  STRAIOHT-FLUTl,  SPIRAIi|  AND  BHEUb 

END  mUM  I 

contact  with  the  work  at  one  time.  The  action,  there 
fore,  is  a  shearing  cut  instead  of  a  pushing  cut.  Tlii' 
mill,  also,  requires  less  power  to  drive  it  and  is  les 
likely  to  produce  chatter. 


MILLING  AND  PLANING 


77 


The  special  form  of  cutter  shown  at  D  is  made  on 
the  same  principle  as  that  shown  at  C,  except  that  it 
is  intended  to  cut  only  on  the  side.  The  spiral  in 
this  case  is  much  more  abrupt,  so  that  the  shearing 
action  is  very  pronounced.  A  cutter  of  this  kind 
gives  excellent  results  on  steel  and  produces  a  su- 
perior fnish  by  virtue  of  its  shearing  cut.  The  flutes 
may  be  nicked  to  break  the  chip;  this  makes  the  cut- 
ting action  easier  and.  is  an  advantage  on  very  tough 
and  wiry  material. 

When  an  end  mill  of  a  greater  size  is  required,  it 
is  evident  that  it  would  not  be  economical  to  make 
both  tool  and  shank  of  high  speed  steel;  hence  the 
shell  end  mill,  E,  has  been  devised.  It  can  be  seen 
that  such  a  mill  is  easily  attached  to  a  stem  or  taper- 
ing arbor  which  fits  the  conical  hole  in  the  mill.  The 
end  of  the  arbor  is  threaded  so  that  the  mill  can  be 
forced  back  onto  the  taper  by  4i|i|.of  a  nut  applied 
to  its  face. 

Shell  end  mills  are  made  in  a  variety  of  ways  to 
suit  different  conditions";  in  the  larger  sizes,  for  in- 
stance, the  body  of  the  tool  may  be  made  of  cast  iron 
or  steel  with  the  cutter  blades  inserted.  When  in- 
serted blades  are  used  it  is  evident  that  the  cost  of 
upkeep  is  much  less  than  when  the  mill  is  cut  from 
the  soMd  metal,  for  a  broken  tooth  can  be  readily 
replaced  with  a  new  one;  furthermore,  an  entirely 
new  set  of  blades  can  be  substituted  for  a  worn  out 
set  at  comparatively  small  expense.  Ordinarily,  mills 
^?  five  iiglpi  in  diameter  are  made  from  a  single' 
piece  of  higfi-speed  or  carbon  steel,  while  those  above 
*is  size  are  made  with  inserted  blades. 


PATTBJUfS 


Slotting  OntlerB.— If  a  straight  slot,  open  at  the 
ends,  is  to  be  cut  in  a  casting  or  other  piece  of  work, 
a  plain  end  mill  such  as  that  shown  in  Figure  42  at 
A  or  B  can  be  used.  But  if  the  slot  is  I-shaped, 
another  type  of  cutter,  A,  Figure  43,  must  he  used. 


FIG.  43.    (a)  tee-slot  CITTTER,     (b)  FISHTAIL  CUTTER 
(C)  TWO-UP  SLOTTING  CUTTER 


Tkm  cutter  is  commonly  spoken  of  as  a  tee-slot  cut- 
ter. It  will  be  noted  that  the  neck  of  the  tool  is 
smaller  than  the  cutter,  so  as  to  permit  under  cut- 
ting the  work,  or  getting  the  tool  down  into  a  slot, 
etc.  This  same  t3rpe  of  cutter  is  also  used  for  cutting 
the  circular  slot  in  a  shaft  when  a  Woodruff  key  is 
to  be  inserted. 

In  many  kinds  of  manufacturing  work  it  is  neces- 
sary to  cut  a  narrow  slot  with  rounded  ends,  as  for 
example  a  slot,  or  spline"  as  it  is  more  frequently 
called,  in  a  shaft  in  which  a  key  of  rectangular  sec- 
tion is  to  be  fastened  to  act  as  a  driver  for  a  pulley 
or  a  gear.   There  are  several  ways  to  cut  such  a 


MIiIiINQ  AND  PLANING 


79 


spline,  but  such  cutters  as  shown  at  B  or  C,  Figure 
43,  are  most  useful.   The  cutter,  B,  is  termed  a  fish- 
tail cutter  from  its  resemblance  to  a  fish's  tail.  The 
cutter,  C,  is  a  two-lip  slotting  cutter  or  routing  cut- 
ter. Both'  types  are  used  for  the  same  work,  but  the 
latter  is  used  more  frequently  on  cast  iron  to  cut 
directly  mto  a  piece  of  work  to  the  depth  desired; 
then  the  work  is  fed  along  to  the  requiired  distance, 
liie  hshtail  type  is  more  useful  for  steel  work  since 
It  has  better  chip  clearance.    These  tools  are  com- 
monly used  on  the  spUne-miUing  machine  or  on  a 
milling  machine  with  a  spline-miUiug  attachment  for 
cuttmg  slots  and  splines  in  general  manufacturing 

WUx  Ik. 

Angular  and  Specud  Cutters—Various  types  of 
cutters  have  been  developed  for  diflferent  kinds  of 
work,  the  shapes  being  dependent  upon  the  form  to 
be  cut  and  the  manufacturing  conditions  governine 
the  production.  In  making  up  reamers,  drills,  and 
special  tools  of  different  kinds,  special  cutters  are  a 
necessity  in  developing  the  required  forms.  Refer- 

views  shown  at  A  and 
a  mdicate  respectively  the  shape  of  the  cutting  edges 
ot  the  milling  cutters  used  for  cutting  flutes  in 
reamers  and  taps.  C  and  D  are  used  for  fluting  twist 
anils  and  other  work  of  similar  character.  F  and  G 
^^^'^ly  single  and  double  angle  cutters  used 
'drgely  tor  cutting  spiral  mills  or  other  work  when 

Z^l\  ^"^^""^^  *°      °'i"«'i  lies  at  an 

«^le  to  the  axis  of  the  work.  E,  H,  and  K  are  cor- 

'«nng,  concave,  and  convex  cutteHh^^etively 
iHey  are  used  for  a  variety  of  purpbtH^j^iJ 


m 


TOOLS  AND  mKtKmB 


ANGULAR  COTTERS  WITH  THREADED  HQIIS 


Wm.  44.    ANGI7LAB  AND  SPECIAL  TYPES  OF  MILLING  CUTTEES 

work,  the  radii  of  the  cutters  being  made  up  to  suit 
any  particular  piece 'of  work  for  which  they  are  to 
be  used  . 

When  a  piece  of  work  is  to  be  machined  which 
does  not  permit  a  cntter  to  be  ield  on  an  arbor  ex- 
tending on  both  sides  of  the  cutter,  it  may  be  neces- 
sary to  make  up  the  types  shown  at  L  and  M.  It 
is  obvious  that  as  snch  a  cutter  must  be  screwed  on 
to  an  arbor,  as  indicated,  it  must  have  either  a  right- 
hand  or  left-hand  thread  according  to  the  direction 
of  rotation  of  the  spindle.  These  cutters  can  be  made 
up  in  any  form  to  suit  the  class  of  work  on  which 
they  are  to  be  used. 


MILLING  AND  PLANING 


GOULD  AND  EBERHAROT 
PATENT 


Caiter 


Work 


E 


TO.  45.    GEUt-TOOTR  ODTTERS  AND  FORMED  CUTTERS 

6ear-Tootii  and  Formed  Cotters.— In  cutting  the 
teeth  in  spur  gears  the  cutter,  A,  Figure  45,  is  fre- 
quently employed.  This  cutter,  patented  by  Gould  & 
i-berhardt,  Newark,  N.  J.,  is  so  made  that  each  tooth 
;s  of  shghtly  different  form  than  the  one  preceding 
It  and  progressively  removes  metal  left  by  the  pre- 
ceding tooth.  The  value  of  this  method  of  cutting 
"es  in  the  fact  that  the  stock  as  it  is  removed  is 
oroken  np  into  a  great  number  of  small  chips  instead 
M  a  comparatively  small  number  of  wide  chips 


TOOLS  AND  PATTERNS 


The  obvious  advantage  is  that  the  cutting  action  is 
much  easier  and  it  requires  less  power  than  other 
forms  of  cutters.  With  this  type,  used  for  roughing 
only  the  gear  tooth  is  cut  to  its  correct  shape,  leav- 
ing only  a  small  amount  to  be  removed  by  the  finish- 
ing  cutter,  as  shown  at  B  in  the  illustration.  The 
manner  by  which  the  chip  is  broken  up  by  the  cutter 
is  indicated  at  C.  The  ordinary  type  of  ronghmg-out 
or  stocking  cutter  for  gear  teeth  is  of  somewhat 
similar  shape,  but  it  makes  a  cut  like  that  shown  at 
D  Figure  45,  which,  it  will  be  seen  does  not  leave 
an  equal  amount  of  stock  all  around  for  the  fimshing 
cutter  to  remove,  for  this  reason  it  is  not  as  rffeetive 
in  its  work  as  the  other  type. 

In  some  manufacturing  work  unusual  shapes  may 
be  required  cut  from  a  flat  surface  or  stnp  of  metal, 
and  when  the  quantity  demanded  is  sufficient  to  war- 
rant it  the  form  can  be  milled  to  advantage  by  a 
cutter  formed  to  the  correct  shape,  as  indicated  at 
Fi-ure  45.  Let  us  suppose  that  a  number  of  blocks 
are  to  be  made  from  blocks  2  inches  long  to  have  a 
form-Hke  that  indicated.  In  order  to  produce  a  nuin- 
ber  of  pieces  of  this  kind  it  is  only  necessary  to  make 
up  a  cutter  of  the  required  form  and  to  mill  a  num 
her  of  long  strips  on  the  milling  machine.  The  strips 
can  afterward  be  sawed  up  into  short  pieces  each  ot 

which  is  2  inches  long.  ,  i 

All  milling  cutters  are  **relieved''  at  the  bacK  oi 
the  tooth,  in  order  to  provide  chip  clearance  for  chil^ 
removed  from  the  work  by  the  cutting  action  ana 
also  to  prevent  the  back  of  the  tooth  from  rubbiii 
on  the  work  during  the  operation.  Formed  cutters 


MILMNG  AND  PLANING 


83 


like  the  one  shown  at  D,  however,  are  given  a  differ- 
ent kind  of  relief,  called  an  eccentric  relief,  which 
permits  the  cutter  to  be  re-ground  a  number  of  times 
after  it  becomes  dull  without  changing  the  shape  of 
the  piece  milled. 

HisceUaiieous  Cutters. — It  is  obviously  impossible 
to  describe  and  illustrate  every  type  of  cutter  without 
entering  into  a  lengthy  discussion  of  the  subject  of 
milling.  Such  a  discussion  is  unnecessary  here.  The 
descriptions  show  that  varieties  to  meet  every  con- 
dition can  be  made.    Figure  46  shows  a  group  of 
common  cutters  used  for  various  purposes  in  the 
average  factory.    The  cutter,  A,  is  generally  termed 
a  **hob."  It  is  used  for  milling  the  teeth  in  a  worm 
gear,  the  work  being  held  on  an  arbor  either  on  a 
milling  machine  or  a  gear  bobber.  In  making  such  a 
cutter  the  shape  first  produced  is  very  similar  to  a 
worm  gear  and  the  teeth  are  formed  by  cutting  longi- 
tudinal grooves.   Each  of  the  teeth  is  then  relieved, 
and  the  cutter,  is,  hardened  and  ground  ready  for 
work.   A  hob  cutter,  when  used  for  a  worm  gear, 
must  always  be  made  up  specially  for  any  piece  of 
work.    Gear  teeth  of  the  spur  variety,  however,  are 
cut  with  so-called  generating  hobs  on  regular  gear- 
hobbing  machines,  which  can  be  bought  in  stock 
sizes  according,  to  the  pitch  of  the  teeth  an^i  the  kind 
of  machine  on  which  they  are  to  be  used.  Each  hob, 
however,  is  made  for  a  specified  pitch  of  tooth  and 
can  be  used  only  for  this  pitch. 

In  this  connection  an  amusing  incident  occurred 
some  years  ago  in  a  New  England  factory  where 
there  were  a  number  of  apprentices.   One  of  the  ap- 


m  TOOLS  AND  PATTERNS 


TO.  46.    (a)  WORM  HOB  CUTTER,    (b)  SIDE  OB  STRADDM:  Mllir 
mo  COTTEB.    (C)  PLAIN  MHjUHO  CUTTER,     (d)  IN- 
SEBfBD-BLADE  CUTTEB.    (e)  mTEBIMKING 
mUA  CUTfBB 


MIMiING  AND.PIiANING 


85 


prentices  was  sent  to  the  tool  room  by  the  tool  maker 
for  whom  the  boy  was  working,  who  told  him  to  get 
**the  hob  used  for  the  big  gear  on  Machine  No.  1272.'' 
On  the  way  to  the  tool  room  the  boy  forgot  the  num- 
ber 0*  the  machine,  but  nevertheless  he  asked  the 
tool  crib  man  to  "give  me  a  hob  for  a  big  gear." 
*'What  machine  is  it  for?''  the  man  asked  him.  **0h, 
I  don't  remember  the  number  of  the  machine,  but  you 
better  give  me  the  biggest  one  you've  got  'cause  it's 
a  big  gear.''  Needless  to  add,  he  was  told  to  **beat 
it,  and  get  the  machine  number." 

The  cutter,  B,  Figure  46,  is  a  side-milling  cutter 
used  as  a  single  cutter  for  side  milling  or  for  facing 
a  piece  of  work.  It  is  also  frequently  used  in  gangs 
of  two  or  more  spaced  the  required  distance  apart 
for  straddle  milling."  For  example,  if  a  boss  on 
the  end  cff  a  lever  needs  to  be  faced  on  each  side, 
two  side-milling  cutters  would  be  properly  spaced  on 
an  arbor  in  the  milling  machine  so  that  the  distance 
between  the  cutters  would  be  the  same  as  the  width 
of  the  finished  boss  on  the  lever.  Given  the  proper 
kind  of  fixture  for  holding  the  work,  then,  a  great 
number  of  pieces  could  be  machined  one  after  the 
other  with  perfect  uniformity  until  the  cutters  were 
so  worn  as  to  require  readjustment. 

For  heavy  work  of  large  diameter  inserted-tooth 
facing-mills,  D,  Figure  46,  are  used  both  singly  and 
in  groups  for  the  same  purpose  as  the  side  cutter,  B. 
Cutters  of  this  kind  are  largely  used  for  making 
heavy  facing  cuts  on  both  cast  iron  and  steel.  They 
will  also  produce  good  results  on  aluminum  or  brass. 
On  vertical  milling  machines  and  multiple  spindle 


86 


TOOLS  AND  PATTERNS 


nuidiiiies  this  type  of  eatter  is  extensively  used  for 
general  manufacturing. 

The  plain  milling  cutter,  C,  is  intended  only  for 
surfacing  or  milling  broad  flat  surfaces.  It  is  most 
frequently  used  for  milling  steel.  Frequently  this 
cutter  is  set  up  with  two  or  more  side-milling  cutters 
to  mill  a  flat  surface  and  at  the  same  time  to  straddle 
mill  both  sides.  It  will  be  noted  that  the  teeth  on  the 
cutter  are  milled  spirally  in  such  a  way  that  as  the 
cutter  revolves  each  tooth  engages  the  work  progress- 
ively with  a  shearing  cut,  thereby  producing  a  very 
fine  finish  with  little  likelihood  of  chatter.  It  is  well 
to  state  lit  this  point  that  no  matter  what  style  d 
cutter  may  be  used  on  any  piece  of  work  some  chat- 
ter may  result.  Loose  gibbing  (loose  attaching)  on 
the  table  of  the  machine  is  a  frequent  cause,  the 
remedy  for  which  is  apparent.  Another  cause  is  a 
poorly  designed  fixture  for  holding  the  work  or  an 
inefficient  method  of  clamping  the  work  in  the  fixture. 
Still  another  is  the  use  of  an  incorreet  speed  or  im- 
proper  feed,  or  a  combination  of  both,  which  will  be 
discussed  in  a  later  chapter. 

Interlocking  Cutters. — ^In  many  processes  of  manu- 
facturing occasions  arise  when  it  is  necessary  to  mill 
a  slot  in  the  work  to  a  specified  size  within  close 
Umits  of  accuracy.  The  ordinary  type  of  side- 
milling  cutter,  B,  Figure  46,  if  used  for  this  work 
soon  becomes  so  worn  on  the  sides  that,  after  grind- 
ing a  lew  times,  it  is  a  trifle  under  size  and  does  not 
cut  the  slot  to  the  required  dimensions.  When  such 
a  condition  as  this  arises,  therefore,  an  interlocking 
cutteri  E,  Figure  46,  should  be  used.   This  illustra- 


MIIililNe  ANB  PLANING 


87 


tion  shows  that  the  cutter  is  really  a  double  cutter, 
made  up  of  two  parts  which  fit  into  each  other  in 
such  a  manner  that  every  other  tooth  laps  over  an 
imaginary  center  line  drawn  around  the  circumfer- 
ence of  the  cutter.  By  this  arrangement  the  teeth 
of  the  cutter  may  be  adjusted  by  placing  a  disc  of 
thin  paper  between  them  when  they  become  slightly 
worn,  the  paper  disc  being  made  thick  enough  to 
compensate  for  the  wear  caused  by  hard  usage  and 
frequent  regrinding.  Such  a  cutter  can  be  kept  up  to 
accurate  size,  and  will  always  produce  a  piece  of 
work  within  the  required  limits. 

Planing  Tools.— Surfaces  requiring  the  greatest  ac- 
curacy are  often  planed  instead  of  being  milled.  This 
is  particularly  the  case  with  heavy  castings  such  as 
machine  beds  and  heavy  fixtures,  or'  parts  of  ma- 
chines which  are  a  sliding  fit  on  each  other— such  as 
the  cross  slide  on  a  turret  lathe,  the  carriage  on  an 
engine  lathe,  the  table  of  a  milling  machine  and  other 
work  of  similar  character.  In  large  manufacturing 
work— the  building  of  locomotives,  steam  engines, 
compressors,  or  printing  presses— the  planer  is  a  valu- 
able adjunct;  but  for  smaller  manufacturing  the  mill- 
ing machine  is  much  more  largely  used,  not  only  on 
account  of  its  superiority  in  the  matter  of  rapid  pro- 
ductipn  but  also  because  it  does  not  require  so  experi- 
enced an  operator  as  the  planer. 

The  tools  used  in  planing  are  generally  single 
lorged  tools  of  a  nature  similar  to  those  used  on  the 
engine  lathe.  There  is  a  little  difference  in  the  shapes 
of  the  tools,  however,  since  in  the  one  case  the  work 
IS  revolving,  while  in  the  other  the  work  is  moving 


88 


TOOLS  AND  PATTBINS 


along  in  a  horizontal  direction.  Except  for  the  fact 
that  planer  tools  are  somewhat  heavier  than  lathe 
tools,  there  is  so  little  difference  in  them  that  it  is 
rather  unnecessary  to  go  into  an  extended  description 
of  them.  It  should  also  be  remembered  that  the 
planer  is  not  used  to  any  great  extent  in  interchange- 
able raiannf actnrey  so  that  the  tools  are  not  so  highly 
specialized  but,  more  frequently,  are  gronnd  in  a 
slightly  different  way  to  suit  the  particular  case. 


CHAPTER  VI 


BEOACHING 

The  Purposes  of  Broaching.— The  process  of  broach- 
ing holes,  either  round  or  rectangular,  is  by  no  means 
new,  but  modem  methods  differ  from  those  in  use  a 
few  years  ago.  In  present-day  practice  the  broach 
is  pulled  through  the  hole  as  a  rule,  while  the  former 
method  favored  a  pushing  action  in  forcing  the  tool 
through.  Strictly  speaking  the  broaching  of  a  hole 
is  a  shaving  operation  produced  by  a  number  of  cut- 
ting edges  on  a  tool  of  suitable  form.  The  teeth  on 
the  broaching  tool  are  so  arranged  that  progressively 
they  come  in  contact  with  the  work  as  the  tool  is 
forced  through.  Each  tooth  is  set  out  beyond  the 
preceding  one  a  few  thousandths  of  an  inch,  the 
amount  being  dependent  upon  the  length  of  the 
broach,  the  kind  of  material  which  is  being  cut,  and 
the  amount  of  stock  which  is  to  be  removed. 

The  design  of  broaches  therefore  must  take  into 
consideration  the  points  mentioned  and  also  the  mat- 
ter of  upkeep— re-grinding  and  replacement  when 
worn.  For  example,  it  would  not  be  economical  to 
design  and  make  up  a  broach  which  was  to  be  used 
only  for  a  couple  of  hundred  pieces  in  as  painstaking 
a  manner  as  though  the  work  consisted  of  several 
thousand  pieces.  It  would  be  the  part  of  wisdom  to 

80 


m 


TOOLS  AND  PATTERNS 


nmke  up  the  tool  as  cheapl|r  m  possible  consistent 
with  good  workmanship;  but  if  several  thousand 
pieces  were  to  be  broaehed  refinements  in  design 
could  be  made  so  that  replacements  could  be  made  as 
easy  as  possible. 

PrtUmiiiaiy  Treatmrat— The  preliminary  require- 
ments in  broaching  a  hole  are  that  the  work  shall  have 
been  previously  drilled  or  bored,  or  that  an  opening  of 
some  sort  in  flie  piece  is  large  enough  to  permit  the 
entry  of  the  small  end  of  the  broaching  tool.  It  is 
also  necessary  to  ensure  that  the  work  can  be  prop- 
erly held  and  so  located  that  the  broaching  operation 
will  be  done  in  the  correct  location  on  or  in  the  work. 
Sometimes  a  previously  drilled  or  reamed  hole  can 
be  used  for  locating  the  work  precisely  by  slipping 
it  onto  a  stud  on  the  face  plate  of  the  machine.  In 
some  eases  the  broach  itself  acts  as  the  locating 
medium. 

In  order  that  the  process  of  broaching  may  be 
more  readily  understood  by  the  reader,  let  us  assume 
that  a  gear  blank  has  been  drilled,  bored  and  reamed, 
and  that  it  is  desired  to  cut  a  keyway  through  it,  as 
in  X,  Figure  47.  In  this  case  the  face  plate  of  the 
broaching  machine  is  provided  with  a  **  pull-bush- 
ing,** as  it  is  called,  in  which  a  slot  is  cut  to  allow 
the  broach,  A,  to  pass  through  it.  This  pull-bushing 
then  acts  as  a  guide  for  the  broach  and  at  the  same 
times  locates  the  work  properly  for  the  operation. 
This  broach,  A,  is  called  a  "keyway"  broach  and 
may  be  purchased  cheaply  in  standard  sizes  from  the 
makers  of  broaching  machines,  or  it  may  be  made  up 
in  the  tool  room  of  any  factory  at  comparatively 


BBOACHING 


91 


A  -  KEV-WAY  BROACH 


O  -  SQUARE  HOLE  BROACH 


Work 


C-  ROUND  HOLE  BROACH 


Work 


0-  RHJR*WY  KEY-WAY  BROACH 


ITO.  47.   SEVERAL  VABIETIES  OF  BBOAOmNO  TOOEB 

small  expense.  One  end  of  the  tool  is  slotted,  so  that 
a  pin  can  be  nsed  to  couple  it  to  the  feed-screw  mech- 
anism of  the  machine.  The  teeth  on  the  broach,  start- 
ing at  the  end  where  the  slot  is,  are  graded  in  such 
manner  that  the  first  tooth  cuts  a  very  shallow 
groove  in  the  work,  the  next  tooth  increases  the 
depth  slightly,  and  the  remainder  of  the  teeth  act  in 
like  manner  progressively.  The  last  iMilil  five  teeth 
m  the  broach  cut  the  full  depth  of  the  slot,  for  the 
purpose  of  assuring  the  accuracy  of  the  work  in  the 
event  that  some  of  the  teeth  become  worn. 

Broaching  a  Square  Hole.— As  a  broaching  cut  of 
any  kind  requires  a  powerful  machine,  it  is  evident 
that  the  wear  on  the  broach  is  very  severe.  There- 


TOOLS  AND  PATTERNS 


for  to  relieve  the  machine  as  far  as  possible  and  also 
to  provide  for  long  life  in  the  broach  itself,  it  is 
customary  in  broaching  a  square  hole  to  drill  the 
work  out  previously  to  a  diameter  slightly  larger 
than  the  distance  across  the  flat  surfaces  of  the 
square,  as  shown  at  Y,  Figure  47.  The  broach,  B,.  is 
the  type  used  for  a  square  hole.  The  slotted  end  is 
cylindrical  and  a  trifle  smaller  in  diameter  than  the 
previously  reamed  hole  so  as  to  act  as  a  pilot  in 
guiding  the  square  portion  of  the  broach  into  the 
hole.  Broaches  of  this  variety  are  made  of  a  single 
piece  of  carbon  steel,  machined  to  the  shape  indi- 
cated, and  carefully  hardened  and  ground  before 
being  used.  The  teeth  also  cut  progressively  as  in 
the  instance  previously  mentioned,  the  amount  cut 
by  each  tooth  being  slightly  in  excess  of  that  taken 
by  the  tooth  just  ahead  of  it. 

In  broaching  steel,  the  teeth  of  the  broach  are 
usually  well  lubricated  at  the  moment  before  they 
enter  the  hole,  thus  reducing  the  friction  of  the  cut 
and  carrying  away  the  heat  generated.  The  proper 
lubricant  is  determined  by  the  material  which  is  to 
be  cut.  The  various  important  matters  connected 
with  the  subject  of  lubrication,  however,  will  be 
found  in  Chapter  XIX. 

Broaching  a  Round  Hole.— Formerly,  the  proper 
method  of  obtaining  a  cylindrical  hole  to  a  given 
dimension  was  by  the  reaming  process.  The  ordmary 
procedure  was  to  bore  the  hole 'with  roughing  and 
finishing  boring  tools,  leaving  a  few  thousandths  of 
an  inch  of  metal  to  be  removed  by  the  reainer 
Becent  developmOTts,  however,  have  shown  that  a 


BBOACHING 


round  broach  can  be  used  to  better  advantage.  The 
finish  in  the  hole  produced  by  a  broach  is  superior 
to  that  made  by  a  reamer,  and  the  required  size  can 
be  easily  obtained.  In  the  matter  of  upkeep,  also,  the 
broach  is  superior  to  the  reamer,  although  its  first 
cost  may  be  somewhat  higher.  As  to  accuracy,  the 
modem  broaching  machine  can  be  fitted  with  fixtures 
for  holding  the  work  and  locating  it  so  exactly  that 
center  distances  can  be  precisely  maintained.^  As  a 
matter  of  fact  the  broaching  process  may  be  con- 
sidered as  a  precision  operation. 

When  it  is  desired  to  broach  one  hole  in  a  piece 
in  a  definite  relation  to  another,  it  is  only  neces- 
sary to  locate  a  stud  on  the  face  plate  of  the  machine 
at  the  proper  distance  from  the  center  hole  and  pro- 
vide a  broach  of  suitable  form.  It  will  be  under- 
stood that  when  the  hole  is  a  single  one  and  not 
located  accurately  with  relation  to  some  other  one 
in  the  work  the  broaching  machine  centers  the  broach 
in  the  work  by  the  previously  reamed  or  bored  hole. 
In  such  a  case  no  special  fixture  is  needed. 

In  the  case  illustrated  in  Figure  48,  a  very  accurate 
location  is  necessary  between  the  two  centers,  A  and 
B,  in  the  work,  C,  an  automobile  connecting  rod. 
Prior  to  the  operation  shown,  the  hole,  A,  has  been 
<Inlled  and  broached  to  the  proper  size,  no  fixture 
being  used  in  the  operation  and  the  hole  itself  acting 
as  a  locating  point.  For  the  operation  shown  the 
^vork  is  located  on  a  stud  on  the  face  plate  by  the 
hole,  A,  which  is  located  the  correct  distance  from 
he  other  hole,  B,  the  latter  being  the  center  line  of 
tlie  broach  itself.  For  work  of  this  nature  the  broach- 


m  TOOLS  AND  PATTERNS 


no.  48.    METHOD  OF  BROACfflNG  A  CONNECTINO  BOO 


ing  machine  must  be  furnished  with  supplementary 
equipment  in  the  nature  of  a  support  table  and  slide 
as  indicated  in  the  illustration.  The  slide,  D,  sup- 
ports the  end  of  the  broach  and  centers  it  correctly 
as  it  is  pulled  through  the  work.  Most  excellent 
work  can  be  done  with  such  equipment.  The  broacli, 
C,  Figure  47,  is  used  for  round  holes,  and  differs  from 
B  only  in  shape.  Naturally  the  teeth  are  formed  by 
a  series  of  progressive  rings  instead  of  squares. 

Pour-way  Keyway  Broaches.— In  automobile  and 
machine  tool  work  it  is  sometimes  necessary  to  cut 
four  keyways  in  a  piece  of  work  which  may  be  either 
a  sliding  fit  or  a  close  fit  on  a  shaft,  four  keys  being 
set  into  it  for  the  purpose  of  providing  an  efficient 
method  of  driving.  When  such  a  broaching  job  i? 
to  be  done  the  broach  is  made  up  in  a  somewhat  dif 
ferent  way  than  those  previously  described.  In  Fig- 
ure 47,  D,  the  cutting  blades,  F,  are  made  up  separ- 
ately and  are  fitted  to  the  body  of  the  broach,  E,  by 
some  approved  metlii||||ieh  as  the  screws  indicated 


BlOACHINa 


in  the  drawing.  Other  methods  of  fastening  are  also 
used,  and,  generally  speaking,  a  method  should  be 
adopted  which  permits  adjustment  and  holds  the 
Wades  firmly. 

^OMJitti  For  Xrregular  Holes.— Irregular  forms 
such  as  internal  gears  of  some  kinds,  ratchet  teeth,' 
•md  many  other  varieties  of  holes,  can  be  broached 
to  advantage  providing  that  the  production  is  large 
enough  to  warrant  the  necessary  expense  of  procuring 
he  broaches.  A  few  shapes  which  can  profitably  be 
woached  are  indicated  in  Figure  49.  The  form.  A, 
IS  an  mtemal  cam,  %-inch  thick,  made  of  steel.  Sev' 


mi 


TOOIiS  AND  PATTERNS 


ef&l  of  these  pieces  are  generally  broached  at  one 
time  without  the  use  of  a  fixture,  the  broach  being 
formed  to  the  required  shape.  The  form,  B,  is  out 
of  the  ordinary  and  serves  to  show  the  variety  of 
work  which  can  be  done  on  a  broaching  machine. 
The  four  rectangular  holes  are  made  concentric  with 
the  center  hole,  the  material  being  steel.  An  internal 
spur  gear  is  shown  at  C,  and  a  sprocket  with  an  in- 
ternal ratchet  is  indicated  at  D.  Both  of  these 
broaches  are  of  the  solid  variety,  formed  to  the  cor- 
rect shape  and  the  teeth  cut  in  the  same  manner  as 
those  previously  described. 


I 


CHAPTEE  VII 


SUEFACE  AND  CYLINDRICAL  GKINDINQ 

Grinding  Material.— Many  persons  take  an  errone- 
ous view  of  the  process  of  grinding  and  consider  that 
it  is  adapted  only  to  the  truing  up*  of  parts  which 
have  been  hardened  and  which,  therefore,  cannot  be 
cut  by  the  ordinary  type  of  tool.  As  a  matter  of  fact 
the  up-to-date  factory  employs  grinding  for  many 
parts  which  have  not  been  hardened  at  all.  When 
parts  have  been  hardened  they  are  likely  to  be  more 
or  less  distorted  and  out  of  true,  and  these  distorted 
parts  can  be  corrected  by  grinding  with  a  wheel  com- 
posed of  emery,  carborundum,  alundum,  or  other 
abrasive. 

Many  of  the  compositions  used  for  making  grind- 
ing wheels  are  produced  by  artificial  means,  but  the 
chief  natural  abrasives  are  emery  and  corunduin,  the 
latter  being  used  to  a  greater  extent  than  emery.  The 
abrasives  produced  artificially  are  composed  princi- 
pally from  carbide  of  silicon  and  bauxite  fused  at  a 
high  temperature  in  the  electric  furnace.  The  vari- 
ous trade  names  of  the  artificial  abrasives  and''ll|l|^ 
composition  and  uses  are  as  follows: 

Adamite  is  used  in  wheels  for  grinding  materials 
such  as  steel  either  soft  or  in  a  hardened  state.  It 
IS  an  artificial  abrasive  made  in  Austria,  and  is  com- 

0? 


96 


TOOLS  AND  PATTERNS 


posed  of  alumiinmi  oxide  with  certain  other  materials 
fused  together  in  an  electric  furnace  at  a  high  tem- 
perature. 

Aloxite  is  used  in  wheels  for  grinding  the  same 
class  of  materials  as  that  mentioned  above.  It  is  a 
product  of  the  Carborundum  Co.,  and  is  made  by  a 
special  process  from  aluminum  oxide  crystals  pro- 
duced by  fusing  mineral  bauxite  in  an  electric  fur- 
nace. 

Boro-carbone  is  a  trade  name  for  another  product 
of  bauxite,  as  manufactured  by  the  Abrasive  Material 
Co.  This  abrasive  is  used  for  grinding  materials 
which  i)ossess  high  tensile  strength. 

Carbide  of  Silicon  is  used  for  grinding  brass,  cast 
iron,  and  other  materials  which  possess  low  tensile 
strength.  It  is  a  composition  of  coke  and  sand  fused 
in  the  electric  furnace.  This  material  also  is  a  prod- 
uct of  the  Abrasive  Material  Co. 

Carbolon  is  used  for  materials  having  a  low  tensile 
strength.  It  is  made  by  the  Vitrified  Wheel  Co.,  from 
coke  and  sand  fused  in  the  electric  furnace. 

Carborundum  is  a  very  well  known  abrasive  which 
is  a  chemical  combination  of  carbon  and  silicon  fused 
at  a  temperature  of  7000  degrees  Fahrenheit. 

Crystolon  is  an  artificial  abrasive  made  by  the  Nor 
ton  Co.  It  is  particularly  suited  to  the  grinding  of 
cast  iron,  brass,  and  other  materials  of  low  tensile 
strength.  The  chief  ingredients  of  this  abrasive  are 

carbon  and  dlicon.  . 

Corundum  is  a  mineral  derived  from  native  alumina 
and  is  the  purest  of  all  the  natural  abrasives.  It  is 
also  produced  by  artificial  means  in  an  electric  fur 


CTEIMDIMe 


99 


nace  and,  next  to  the  diamond,  it  is  the  hardest  of  all 
known  materials..  In  reality  it  is  nothing  more  than 
crystallized  aluminum  oxide,  whether  obtained  by 
either  natural  or  artificial  means.  The  artificial 
product  can  be  obtained  in  many  grades  suited  to 
many  varieties  of  work. 

Emery  is  used  for  obtaining  a  fine  finish  on  bearing 
surfaces,  ball  races,  and  the  like;  but  as  an  abrasive 
in  manufacturing  grinding  processes  emery  has  been 
largely  superseded  by  some  of  the  other  materials 
mentioned  in  the  foregoing  list.  While  it  is  unex- 
celled for  certain  kinds  of  work,  it  does  not  possess 
the  hardness  nor  does  it  have  the  free  cutting  quali- 
ties of  some  of  the  other  abrasives. 

Grinding-Wheel  Shapes.— Grinding  wheels  are  made 
in  a  variety  of  sizes  and  in  shapes  of  every  kind  for 
cylindrical  work,  shouldered  work,  forming,  internal 
work,  surfacing,  and  so  on.   Some  of  the  more  com- 
mon forms  are  shown  in  Figure  50,  although  these 
are  but  a  very  few  of  the  many  kinds  and  forms  in 
use.   In  selecting  a  wheel  shape  for  any  piece  of 
work,  it  is  obvious  that  several  things  must  be  con- 
sidered—the kind  of  machine  to  be  used  on  the  work, 
for  instance,  or  the  form  to  be  ground,  or  the  method 
of  presenting  the  wheel  to  the  work  itself.  So  many 
factors  affect  the  shape  of  the  wheel  to  be  used,  in 
fact,  that  it  is  out  of  the  question  to  illustrate  and 
describe  the  various  kinds  in  a  work  of  this  kind; 
moreover  such  a  description  would  be  of  no  material 
value  to  an  executive  for  it  would  entail  so  great  an 
amount  of  descriptive  matter  as  to  be  confusing 
I'ather  than  enlightening.   JFor  the  specific  cases  of 


100  TOOLS  AND  PATTERNS 


mSO.   VARIOUS  SHAPES  OF  GRINDING  WHEELS 


grinding  illustrated  in  this  book  tlie  style  of  wheel 
shown  in  any  particular  case  may  be  considered  as 
the  ordinary  shape  used  for  the  work. 

Surface  Orindfaig  Mettuids.— When  a  plane  surface 
which  has  been  hardened  or  which,  nnhardened,  needs 
careful  finishing,  it  is  frequently  desirable  to  grind 
the  surface  to  the  required  finish.  Some  machines 
which  are  used  for  surface  grinding  are  adapted 
principally  to  light  work  requiring  a  high  degree  of 
accuracy,  such  as  die  blocks  and  other  tool  room 
work,  while  others  are  intended  for  general  manu- 
facturing. When  work  is  to  be  ground  on  a  surface 
grinder  it  is  of  the  highest  importance  that  it  should 
be  held  in  such  a  way  that  there  can  be  no  spring 
or  distortion  arising  from  an  improper  method  of 
clamping.    Magnetic  chucks— that  is,  naagnetized 


GMNDIMG  101 

plates— are  largely  used  for  holding  work  which  is 
to  be  finished  in  this  way,  although  there  are  cases 
which  require  some  more  positive  clamping  action. 
The  description  of  fixtures  for  holding  work  during 
grinding  operations  is  dealt  with  in  Chapter  XVI. 

Several  methods  can  be  employed  when  a  piece  of 
work  is  to  be  finished  accurately  to  a  plane  surface, 
and  the  one  selected  depends  only  upon  the  accuracy 
required  in  the  finished  product.  Thus  for  a  moder- 
ately good  commercial  job,  two  milling  cuts—one 
roughing  and  the  other  finishing— may  be  taken  with 
satisfactory  results;  this  method  is  suitable  for  com- 
paratively narrow  surfaces,  such  as  the  flanges  on  a 
transmission  case  in  automobile  construction  or  other 
work  of  similar  character.  For  the  surfacing  of  a 
machine  bed  or  the  finishing  of  the  plane  portions 
of  locomotive  cylinders,  the  planing  operatidn  will  be 
most  suitable.  But  for  accurate  die  work  and  for 
gauges  and  the  like  a  surface  grinding  operation  or 
even  a  lapping  operation*  may  be  necessitated. 
Also  for  many  operations  in  general  manufacture 
where  surfaces  require  a  high  finish  within  very  close 
limits,  the  surface  grinding  operation  offers  many 
mducements;  for  example,  in  the  finishing  of  rifle 
hammers  over  a  hundred  pieces  may  be  laid  on  a 

magnetic  chuck  and  ground  both  accurately  and 
quickly. 

If     ^^PP*"/  is  not  usuaHy  a  manufacturing  process.  Primarily 

ith  «n  ^'vf^  rubbing  two  surfaces-cyUndrical  o?  puS^ 
^  ^"^r  t^^e  surfac^  Fine 

gages  are  lapped  to  produce  absolutely  accurate  work.  Lapping  is  a 

*^        "^^"^  ""^"^^^  proLses  of 


1CX2 


TOOLS  AND  PATTEINS 


A       A  I 


1 


,»Table 


work 


\  Metgnefic  Chuck 


3 


Sia.  51.   SURFACE  GRINDING  METHODS 


OBINDlMe 


103 


Beferring  to  Figure  51  the  upper  illustration  shows 
a  piece  of  work,  A,  with  a  flat  surface,  such  as  a  die, 
which  is  to  be  ground  after  it  has  been  hardened.  In 
such  work  a  machine  having  a  horizontal  spindle  is 
employed  and  s£  thin  wheel  is  used.  The  work  table 
reciprocates — amoves  back  and  forth — under  the  wheel 
and  feeds  transversely  at  the  end  of  each  stroke,  so 
that  the  entire  surface  of  the  work  is  ground  in  a 
series  of  parallel  cuts.  The  wheel  spindle  is  so  ar- 
ranged that  it  can  be  raised  or  lowered  by  a  screw 
with  micrometer  adjustment,  thus  very  accurate  work 
is  easily  produced.  Strictly  speaking,  a  piece  of  work 
which  is  to  be  ground  on  this  type  of  machine  is 
more  often  found  in  the  tool  room  than  in  general 
manufacturing,  although  the  machine  can  be  adapted 
to  certain  classes  of  high-grade  manufacture. 

The  work,  B,  gives  an  excellent  example  of  grind- 
ing, the  work  involved  being  a  cast  iron  ring  which 
is  to  be  accurately  ground  to  a  uniform  thickness. 
In  this  case  also  a  magnetic  chuck  is  used  to  hold 
the  work  and  a  rotary  table  is  employed.  The  spindle 
of  the  machine  moves  back  and  forth  over  the  surface 
of  the  ring  as  indicated  by  the  arrows  in  the  Elus- 
tration.  The  wheel  used  for  this  class  of  work  is 
sunilar  to  that  used  in  the  previous  example,  and  also 
this  kind  of  grinding  is  used  principally  with  work 
which  has  been  previously  finished  to  within  a  few 
thousandths  of  an  inch  of  its  required  size.  It  is  well 
suited  to  the  finishing  of  packiing  rings  for  steam 
engines,  automobiles,  compressors,  and  the  like. 

For  heavier  manufacturing  and  more  severe  cuts 
on  larger  work,  a  machine  of  a  different  type  is  more 


m 


TOOLS  AND  PATTERNS 


frequently  used,  which  has  the  spindle  nearly  vertical 
but  with  a  very  slight  inclination  to  provide  for  clear- 
ance  behind  the  cutting  edge  of  the  wheel.    In  an 
example  of  this  kind,  it  will  be  noted  that  the  wheel 
is  shaped  like  a  cup,  usually  called  a  cup  wheel.  The 
work,  C,  may  be  held  on  the  table  of  the  machine  by 
means  of  a  magnetic  chuck  or  by  clamps,  depending 
upon  its  shape  and  the  material  from  which  it  is 
made   For  long  work  a  machine  having  a  reciprocat- 
ing table  is  often  used,  and  it  is  ottm  possible  to 
have  several  pieces  on  the  table  at  the  same  time. 
For  this  kind  of  grinding  the  wheel  should  be  of  suffi- 
cient  size  to  cover  the  entire  width  of  the  work.  The 
speeds  and  feeds  at  which  different  kinds  of  grinding 
are  done  will  be  considered  in  Chapter  XX. 

Qylindrical  Grinding.— In  cylindrical  grinding  the 
work  is  frequently  held  on  centers  when  it  is  of  such 
a  nature  that  one  end  can  be  dogged*  for  the  purpose 
of  driving.  But  it  is  not  always  that  centers  can  be 
msed  on  cylindrical  work,  and  the  chuck  is  frequently 
used  for  the  purpose.  In  such  cases  it  is  of  extreme 
importance  to  arrange  the  holding  device  m  such  a 
way  that  it  will  not  distort  the  work.  As  in  surface 
grinding  the  pieces  to  be  ground  may  have  been 
hardened  previously  or  they  may  be  soft,  but  in 
either  event  the  operation  of  grinding  and  the  method 
of  presenting  the  work  to  the  wheel  are  identical. 
The  shape  of  the  wheel  used  for  cylindrical  gnnd- 

dof  to  a  simple  sort  of  clamp  used  for  cyllndri^l  ^-ork  jo 
act  M  a  means  of  driving.    Several  types      ^ogs  can  l^und 

S^rrmachlne  shop.   ^.^^  f^"^^^ J^^JL^fJ^^ 

hold  the  work  firmly  and  a  tatt  wMdi  enters  a  slot  in  to  f 

and  acts  as  a  driver. 


GRINDING 


105 


ing  is  usually  like  that  shown  in  Figure  52  at  A,  al- 
though variations  of  the  shape  occur  to  suit  different 
ccnditions.  Let  us  suppose,  for  example,  that  a  piece 
of  work  of  cylindrical  shape  is  to  be  ground,  and  that 
at  the  end  of  the  ground  surface  there  is  a  fillet" 
which  is  also  to  be  ground.  In  such  a  case  the  wheel 
which  would  come  in  contact  with  the  fillet  would  be 


™.  52.  omNDBiCAii  Mm  ihtsbnal  QBiNiUNo  WErmjm 


106 


TOOLS  AND  PATTERNS 


so  shaped  that  it  would  finish  the  form  at  the  mi  of 
the  stroke. 

If  there  are  several  diameters  to  be  ground  and  a 
great  number  of  pieees  are  to  be  finished^  it  is  com- 
mon to  make  a  separate  operation  for  each  diameter. 
The  reason  for  this  is  that  the  diameter  stops  and 
indieatiiig  dial  on  the  machine  can  be  set  for  repeti- 
tion work  to  better  advantage  if  a  single  diameter  is 
handled  at  one  time. 

When  cylindrical  work  is  to  be  ground  up  to  a 
shoulder  and  leave  a  sharp  comer,  it  is  customary 
to  provide  a  nick  close  to  the  shoulder  so  that  the 
wheel  can  **run  out''  at  this  point,  as  shown  at  B, 
Figure  52. 

Bztenial  Taper  Woik.— When  a  piece  of  taper 
work  is  to  be  ground  the  process  is  practically  the 
same  as  for  straight  cylindrical  work,  except  that 
the  machine  carriage  is  swung  to  the  proper  angle  to 
generate  the  correct  taper.  The  form  of  the  wheel 
is  the  same  as  that  shown  at  Figure  52,  and  the 
method  of  dogging  and  centering  the  work  is  also 
fhe  same. 

Xxismal  fomi  Qiindiog.— For  some  work  where 
a  form  of  a  prescribed  shape  is  to  be  ground  on  the 
outside  of  a  cylindrical  piece,  the  wheel  is  fed  di- 
rectly into  the  work  until  the  proper  depth  is  reached, 
as  indicated  in  Figure  52,  C.  The  process  of  form 
grinding  has  lately  been  developed  to  a  great  ex 
tent  in  the  grinding  of  such  forms  as  shrapnel,  nfle 
barrels,  and  other  forms  which  have  to  do  with  mm- 
tion-making  and  ranaU  arms.  In  grinding  a  shrapnel 
shell,  for  example,  the  wheel  for  one  operation  is 


eUNBINO 


107 


formed  to  take  the  curve  on  the  end  of  the  shell, 
while  in  the  operation  of  grinding  the  straight  por- 
tion of  the  body  a  wide  wheel  is  used  for  one  portion 
and  a  narrow  wheel  on  another  part.  In  grinding 
rifles,  the  barrel  is  usually  ground  at  an  approxi- 
mately central  location  on  the  length  of  the  barrel 
to  provide  a  smooth  surface  for  the  steady-rest;  the 
tapers  are  then  ground  with  a  formed  wheel  accord- 
ing to  their  variety  and  shape,  and  the  cylindrical 
surfaces  are  handled  in  the  usual  manner.  If  there 
are  any  tapered  surfaces  on  the  barrel,  these  may  be 
either  ground  with  a  formed  wheel  or  the  grinding- 
wheel  carriage  can  be  set  over  to  the  required  angle 
for  generating  the  taper. 

Internal  Grinding.— The  process  of  internal  grind- 
ing is  applicable  to  either  straight  or  tapered  sur- 
faces, but  the  work  must  be  performed  with  an  in- 
ternal attachment,  such  as  that  shown  at  E,  Figure 
52.  The  wheel,  D,  in  this  case  is  of  much  smaller 
size  than  the  type  of  wheel  used  for  external  grind- 
ing, although  it  is  practically  the  same  shape.  The 
process  of  internal  grinding  is  particularly  useful  in 
the  making  of  bearing  bushings  and  other  work  of 
similar  character.  The  work  may  be  either  straight 
or  tapered;  both  kinds  can  be  handled  with  equal 
facility  providing  that  the  angle  of  the  taper  is  not 
too  great  for  the  carriage  to  accommodate  it. 

In  the  example  shown,  the  work  has  been  previ- 
ously machined  and  a  sufficient  allowance  has  been 
njade  for  grinding  before  the  hardening  operation. 
Ihe  work  is  held  in  a  special  form  of  chuck  as  indi- 
cated, and  the  wheel,  D,  passes  back  and  forth  in  the 


108 


TOOLS  AND  PAfTBBNS 


work  until  the  desired  diameter  has  beea  ground. 
Suitable  adjustments  for  diameter  can  easily  be  made 
on  the  machine,  and  it  is  entirely  possible  to  keep 
manufacturing  work  within  a  limit  of  0.00025  inches 
on  the  diameter.  Many  varieties  of  chucks  are  used 
for  this  class  of  work  and  some  of  these  are  of  par- 
ticular interest  in  the  provision  made  for  locating, 
holding,  and  driving  the  work  without  distortion. 
These  will  be  dealt  with  more  specifically  in  Chapter 

cylinder  Orindinf.— In  automobile  manufacture, 
and  also  in  the  manufacture  of  compressors  and  other 
work  of  this  kind,  the  process  of  grinding  the  inside 
of  the  cylinders  is  extremely  important.    For  this 
purpose  a  cylinder  grinding  machine  has  been  de- 
veloped by  the  Heald  Machine  Co.,  which  operates 
on  a  dilferent  principle  from  those  used  in  ordinary 
internal  cylindrical  grinding.  It  may  be  noticed  that 
in  the  preceding  example  of  internal  grinding,  the 
work  revolves  around  its  own  center  and  different 
diameters  are  ground  by  re-setting  the  wheel  spindle. 
In  the  Heald  cylinder  grinding  machine,  however, 
the  work  is  so  arranged  that  it  does  not  revolve  but 
the  wheel  spindle  is  given  a  double  movement— that 
is,  a  rapid  turning  movement  of  the  wheel  on  its  own 
center  and  an  eccentric  rotary  motion  of  the  spindle 
itself.   The  spindle  is  so  arranged  that  it  can  be  set 
sufficiently  eccentric  to  the  center,  within  the  capacity 
of  the  machine,  to  describe  a  circle  equal  to  the 
diameter  to  be  ground.  Pieces  such  as  an  automobile 
cylinder,  especially  cast  '*en  bloc,"  can  be  arranged 
on  the  carriage  of  the  machine  so  that  one  hole  can 


GRINDING  109 

bo  ground  to  size  and  the  carriage  set  over  the  cor- 
rect center  distance  to  grind  the  other  cylinders. 
Other  data  in  regard  to  the  grinding  of  automobile 
cylinders  will  be  found  in  Chapter  XVI,  Grinding 
Fixtures. 


CHAPTER  Vin 


SHOP  EQUIPMENT 

Staadttd  l^idpiMBir-Aiiy  factory  which  is  in- 
tended to  produce  work  at  a  minimuiii  expense  must 
be  properly  equipped  in  its  various  branches.  The 
toal  crib  must  be  well  supplied  with  all  standard 
sizes  of  drills,  connterbores,  reamers,  boring  tools, 
tape  and  dies,  and  all  the  other  im^emente  which 
may  be  assumed  to  be  a  part  of  the^  tool  crib  equip- 
ment. Such  tools  as  milUng  fixtures,  drill  3igs,  bor- 
ing fixtures,  and  the  like,  also  form  a  part  ot  the 
equipment,  but  these  are  so  varied  that^  they  can- 
not be  considered  as  standard  equipment.  Cutting 
tools  which  lose  their  cutting  properties  when  m 
must  be  taken  care  of  by  resharpening,  and  the  tool 
crib  should  be  provided  with  the  necessiury  grinding 
machines  for  drills,  reamers,  cutters,  and  forged  tooa 
In  addition  to  the  above,  there  are  certam  oth 
tools  which  may  be  considered  more  nearly  a  pa 
of  the  actual  shop  equipment.    These  tools  are  J 
the  nature  of  surface  plates,  straight-edges  parall^ 
V^blocks,  C^clamps,  vises,  etc.    Also,  certain  otn 
instruments,  such  as  surface  gauges,  micrometers 
large  size,  calipers,  special  gauges  such 
ta^r  sockets,  thread  gauges,  and  other  i««trumenj 
for  determining  standard  shapes,  tapers,  and  so 
should  be  provided. 

110 


SHOP  EQUIPMENT 


111 


The  toolmaker  is  ordinarily  considered  to  have  an 
equipment  of  tools  of  his  own,  such  as  small  size 
micrometers,  calipers,  surface  gauges,  squares,  and 
protractors;  and  although  some  of  these  tools  may  be 
included  in  the  shop  equipment,  they  are  more  in  the 
nature  of  special  instruments  sued  for  checking  pur- 
poses and  for  testing.  Omitting  tools  of  this  kind 
from  the  discussion,  then,  we  have  as  a  part  of  the 
shop  equipment  the  tools  that  are  in  daily  use  and 
kept  in  the  tool  crib  strictly  for  the  use  of  the  work- 
men in  producing  work  to  the  best  advantage.  We 
have  also  the  tools  which  are  fastened  in  place,  such 
as  vises  which  are  bolted  to  benches  all  around  the 
shop. 

Surface  Plates.— Keferring  to  Figure.  53,  the  upper 
illustration.  A,  shows  a  form  of  surface  plate  which 
should  be  considered  as  a  part  of  the  standard  equip- 
ment of  any  factory.  Plates  of  this  kind  are  made  of 


."'ffibS 


1 

1  1 

* 

1 

no.  53.    SURFAOB  PLATES  AND  STBAI0HT  IDQES 


112 


TOOLS  AND  PATTEBNS 


east  iron,  well  ribbed  so  that  they  will  not  easily 
get  out  of  alignment.   The  surface  of  the  plate,  B, 
has  been  planed  and  scraped  to  a  perfect  plane,  so 
that  it  can  be  used  for  testing  other  surfaces  or  for 
the  fitting  of  parts.  Several  of  these  plates  of  dif- 
ferent sizes  can  be  fonnd  in  any  toolroom  set  up  here 
and  there  on  the  workmen's  benches.  When  a  piece 
of  work  is  to  be  tested  or  laid  out  with  a  scriber  or 
surface  gauge,  surface  plates  are  essential.   Also  in 
fitting  another  plate  or  piece  .of  work  which  must  be 
a  perfect  plane,  the  surface  plate,  rubbed  with  a  little 
Prussian  blue,  can  be  brought  in  contact  with  it  m 
such  a  way  that  the  "high  spots"  will  show  a  blue 
mark  from  the  contact  These  blue  marks  can  then 
be  scraped  off  with  a  hand  scraper,  as  described  ib 
Cihapter  L   A  plate  of  this  kind  is  more  often  used 
in  the  toolroom  than  in  any  other  department,  al 
though  every  department  in  the  shop  should  have  one 
or  more  for  testing  purposes,  and  for  gauging  and 

la3ring  out  work. 

Slndgfat-edgM  and  Parallels.— It  is  often  necessary 
to  determine  whether  a  surface  is  straight  or  not,  and 
this  determination  is  also  a  valuable  adjunct  in  set- 
ting  up.  The  ordinary  straight-edge,  C,  Figure  53,  is 
generally  kept  in  the  toolroom  and  taken  out  by  a 
woikman  when  he  needs  it.  It  is  usually  made  ot 
cast  iron,  with  a  face, »,  which  has  been  scraped  to  a 
perfect  plane.  In  order  to  lighten  the  tool  and  maKe 
it  more  convenient  for  a  workman  to  handle,  a  nm- 
ber  of  holes  are  pierced  through  it  as  indicated  m 
the  illustration.  Straight-edges  are  made  m  lengt"^ 
from  18  inches  to  15  feet,  according  to  the  work  tm 


SHOP  EQUIPMENT 


113 


which  they  are  intended;  special  sizes  can  be  obtained 
to  order.  These  straight-edges  are  not  commonly 
used  for  the  smaller  varieties  of  work  nor  for  the 
very  finest  class  of  work. 

Another  type  of  straight-edge,  E,  Figure  53,  usually 
called  a  toolmaker's  knife-edge  straight-edge,  may  oc- 
casionally be  found  in  tool  cribs,  although  it  is  more 
often  a  part  of  the  toolmaker's  personal  tool  kit. 
These  straight-edges  are  used  for  work  that  requires 
extreme  accuracy.  Hence,  they  are  made  from  the 
best  quality  of  steel  treated  with  the  utmost  care  to 
insure  that  they  will  be  straight  and  true.  In  the 
finest  kind  of  toolmaking  work  these  straight-edges 
are  extremely  valuable,  and  the  workmen  who  use 
them  take  the  greatest  care  to  see  that  their  accuracy 
is  not  impaired  through  springing  or  injured  by  be- 
ing dropped. 

Parallels,  F,  Figure  53,  are  found  in  great  variety 
and  in  numerous  sizes  in  the  tool  crib.  They  are  use- 
ful for  setting  up  work  of  more  or  less  irregular 
shape  when  the  work  has  been  previously  machined 
on  one  side  and  can  not  possibly  be  clamped  to  the 
table  of  the  machine  for  a  succeeding  operation. 
Parallels  may  be  made  of  steel  or  of  cast  iron,  de- 
pending on  their  size;  the  smaller  parallels  are  usu- 
ally made  of  steel  and  the  larger  sizes  of  cast  iron. 

Frequently  a  piece  of  work  may  be  set  up  and 
damped  to  a  pair  of  parallels  and  machined  when  it 
niight  otherwise  be  very  difficult  to  hold  the  piece 
Without  a  special  fixture  of  some  sort.  In  fact,  the 
uses  of  parallels  in  any  factory  are  so  iill  and  their 
application  is  so  varied  that  it  is  difficult  to  mention 


114 


TOOLS  AND  PATTERNS 


all  of  their  uses.  It  may  be  said,  however,  that  no 
factory  can  be  called  complete  without  having  as  a 
part  of  its  shop  equipment  a  great  number  of  paral- 
lels of  different  sizes  and  sections. 

Via«8.--0ne  of  the  most  important  things  in 
machining  any  piece  of  work  is  to  hold  it  firmly.  As 
the  shapes  which  are  to  be  held  are  of  so  many 
varieties,  shapes,  and  sizes,  it  is  obvious  that  there 
mnst  be  numerous  types  of  holding  devices  which 
can  be  applied  to  the  work.  The  importance,  there- 
fore, of  the  various  clamps  which  are  used  for  hold- 


m.  54.    HAND  VISES,  C-CIAMPS,  AND  V-BLOCKS 


SHOP  EQUIPMENT 


115 


ing  work,  locating  two  pieces  in  definite  relation  to 
each  other,  and  so  on,  in  all  kinds  of  operations,  can- 
not be  overestimated. 

A  group  of  small  tools  which  can  be  considered  as 
a  part  of  the  standard  equipment  of  any  factory  is 
shown  in  Figure  54.  The  hand  vise,  A,  may  be  used 
for  a  variety  of  purposes  by  the  toolmaker  or  other 
workman.  It  will  be  seen  that  the  jaws  of  the  vise 
are  kept  in  a  state  of  parallelism  by  the  equalizating 
cross,  B.  When  the  thumb-nut  is  operated,  the  jaws 
open  or  close  according  as  the  nut  is  loosened  or 
tightened.  For  holding  a  small  piece  of  work  on 
which  a  filing  operation  is  to  be  done,  for  example,  a 
hand  vise  of  this  kind  is  very  useful;  and  for  numer- 
ous other  operations  which  require  the  holding  of  a 
piece  of  small  work  in  a  certain  fixed  position  this 
tool  is  almost  indispensable.  As  a  general  thing  this 
tool  is  more  frequently  found  in  a  toolmaker 's  kit 
than  in  the  tool  crib. 

It  is  often  necessary  to  hold  two  pieces  of  work 
together  when  some  machining  operation  is  to  be 
performed  on  them— for  example,  when  two  pieces 
are  to  be  drilled  and  reamed  together.  In  such  work 
the  toolmaker 's  clamp,  C,  Figure  54,  is  an  important 
accessory  to  the  tool  crib.  This  clamp  is  really  a 
type  of  hand  vise  in  which  the  two  jaws,  C,  C,  are 
^pped  to  receive  the  thumb  screws,  D.  The  two 
jaws  are  operated  by  means  of  the  thumb  screws,  and 
can  be  tightened  by  the  fingers  upon  a  piece  of  work, 
if  additional  pressure  is  needed,  a  pin  hole  in  the 
end  of  the  screw  can  be  used  as  a  holder  for  a  small 
lever.  Ordinarily  this  clamp  is  used  for  holding  fin- 


lis 


TOOLS  AND  PATTBENS 


mked  pieces  together,  Bot  those  which  are  in  a  rough 
state* 

C-C!lamp«.— When  rough  work  is  to  be  held  firmly, 
or  when  a  piece  of  work  is  to  be  clamped  down  on  a 
machine  or  clamped  against  a  parallel,  the  Cdamp, 
shown  at  E,  Figure  54,  is  generally  used  instead  of 
the  toobnaker's  clamp  previously  mentioned.  This 
C-clamp  is  provided  with  an  anvil,  F,  and  a  screw, 
6,  by  means  of  which  the  necessary  pressure  can  be 
exerted.   The  body  of  the  clamp  is  usually  a  drop 
forging  which  is  capable  of  withstanding  consider- 
able pressure.  C-clamps  should  be  found  in  the  tool 
crib  in  great  variety,  both  as  to  siase  and  also  in  re- 
gard to  the  depth  or  throat  opening  which  determines 
the  sizes  of  work  that  may  be  held.    For  holding 
large  work  on  the  planer  or  milling  machine  and  for 
a  variety  of  other  purposes  in  connection  with  manu- 
facturing, the  C-clamp  is  used  to  a  great  extent  and 
must  certainly  be  included  in  the  shop  equipment. 

V-Bloda.*— When  a  piece  of  round  work  is  to  be 
held  so  that  it  can  be  drilled  or  otherwise  machined 
and  no  fixture  has  been  designed  for  the  work,  one 
or  more  V-blocks,  H  and  K,  Figure  54,  can  be  used 
to  make  np  a  temporary  fixture.  The  particular  type 
illustrated  has  a  groove  along  the  side  to  which  a 
special  form  of  clamp  can  be  applied,  as  indicated  at 
M.  The  arrangement  shown  in  the  illustration  is 
used  for  hoMing  a  tube,  N,  to  locate  it  properly  for 
machining  operations— drilling,  milling,  or  cutting  a 
key-slot.  The  bases  of  the  V-blocks  are  parallel  with 
a  centerline  of  the  V-shaped  cut  in  the  block,  so  that 
when  the  work  is  set  np  on  the  machine  it  will  lie 


SHOP  BQinPMENT 


117 


parallel  to  the  surface  on  which  the  blocks  are 
clamped. 

V-blocks  are  often  used  for  straightening  a  piece 
of  work.  In  this  case  the  work  is  clamped  by  two  of 
the  blocks  in  such  manner  as  to  bring  the  bent  por- 
tion between  the  blocks  where  it  can  be  struck  with 
a  hammer  or  straightened  under  an  arbor  press.  The 
application  of  the  V-block  principle  to  many  forms  of 
mechanical  work  will  be  further  described  in  Chap- 
ters XVII  and  XVin.  ^ 


no.  55.    BENCH  AND  FIFE  VIBES 

Bench  and  Pipe  Vises.— Any  attempt  to  describe 
the  shop  equipment  of  the  factory  without  mention- 
ing the  bench  vise  would  be  very  much  like  a  dinner 
^thout  dessert  or  a  roast  of  beef  without  salt.  The 
feench  vise,  A,  Figure  55,  is  an  ordinary  type  of 
^chinist's  vise  which  is  bolted  to  the  workmen's 
bench  at  frequent  intervals  in  every  department.  The 
we  shown  is  equipped  with  a  swivel  jaw,  B,  by 
^eans  of  which  a  piece  of  tapered  work  can  be  firmly 


118 


TOOLS  AND  PATTERNS 


lieM  without  s&wmm*  A  pin,  C,  is  provided  to  lo- 
cate  this  swivel  jaw  in  a  fixed  position  parallel  to  the 
movable  jaw,  D.  A  tapered  piece  of  work,  ^E,  is 
shown  clamped  in  position  in  the  vise.  It  is  evident 
that  vises  of  this  kind  are  an  absolnte  necessity  in 
any  factory,  no  matter  what  the  product  or  how  large 
the  factory.  There  are  so  many  operations  which  need 
the  assistance  of  a  vise  that  it  would  be  out  of  the  ques- 
tion to  attempt  to  describe  all  of  its  uses. 

When  a  bench  vise  is  to  be  used  for  holding  a  piece 
of  finished  work  or  something  which  must  not  be 
marred,  it  is  often  provided  with  a  set  of  soft  jaws, 
F,  usually  made  of  babbitt  metal  or  copper,  but  some 
times  made  of  sheet  brass  or  tin.  Babbitt  metal  jaws 
are  very  short  lived  and  crush  or  break  very  easily, 
so  that  they  become  useless  in  a  comparatively  short 
time  Copper  jaws  or  those  made  of  heavy  brass 
will  last  almost  indefinitely  if  carefully  used.  The 
vises  in  many  shops  are  provided  with  false  soft  jaws 
for  general  use,  and  babbit  molds  for  making  jaws 
of  this  kind  are  in  common  use. 

The  pipe  vise,  G,  Figure  55,  is  frequently  found 
in  shop  equipments,  although  its  principal  use  is  in 
plumbing  work  and  pipe  fitting.  It  is  a  convenieiit 
accessory  for  shop  use,  however,  although  one  visein 
a  department  is  usually  considered  sufficient.  The 
type  shown  is  provided  with  a  set  of  V-shaped  corm- 
gated  jaws  which  grip  cylindrical  work  and  prevent 
it  from  turning  while  a  thread  is  being  cut.  ine 
upper  jaw  is  operated  by  means  of  the  screw  anj 
h^dle  shown,  and  the  latch,  H,  allows  the  enti^ 
upper  part  of  the  vise  to  be  backed  out  of  the  way. 


CHAPT£R  IX 


MACHINE  EQUIPMENT 

Necessity  for  Proper  Tools.— A  man  may  purchase 
a  machine  at  considerable  expense  and  may  find,  after 
it  has  been  in  use  for  a  while,  that  he  is  not  getting 
as  much  out  of  it  as  he  expected  to.  This  may  be 
for  one  of  several  reasons:  It  may  be  that  the  oper- 
ator  is  inclined  to  loaf  on  the  job;  it  may  be  that  the 
cutting  speeds  and  feeds  are  not  correctly  deter- 
mined; or  it  may  be  that  the  tool  equipment  is  in- 
adequate. Disregarding  for  the  time  the  first  and 
second  cause,  it  is  certain  that  any  machine  to  per- 
form its  functions  in  a  satisfactory  manner  must 
have  a  proper  equipment  of  tools. 

When  the  work  is  of  the  interchangeable  variety 
the  matter  of  tool  equipment  needs  most  careful  con- 
sideration. And  even  for  the  ordinary  machine  equip- 
ment certain  tools  are  indispensable  if  the  work  is 
to  be  turned  out  in  good  style  and  with  a  minimum 
expenditure  for  labor.  The  equipment  of  the  tool 
crib  for  standard  machines  in  any  factory,  therefore, 
should  be  very  complete,  so  that  the  workman  wiH 
never  be  obliged  to  use  a  "make-shift"  method  in 
preparing  to  do  any  piece  of  work. 

When  boring  out  a  drill  jig  for  bushing  holes,  or 
something  of  this  kind,  the  toolmaker,  naturally,  is 


120 


TOOLS  AND  PATTERNS 


obliged  to  use  a  eertam  amount  of  ingeBuity  when 
he  *'sets  up"  work  on  the  machine.  However,  this 
display  of  ingenuity  should  not  be  considered  in  the 
line  of  a  make-shift,  beeause  in  such  work  each  job 
is  a  special  one  and  needs  special  care  in  the  setting 
up. 

In  this  chapter  I  will  consider  only  the  type  of 
tools  which  may  be  considered  as  a  part  of  the 
standard  equipment  and  those  which  should  be  kept 
in  the  tool  crib  as  a  part  of  such  equipment.  Tool 
equipment  for  various  machines  has  been  or  will  he 
taken  up  in  this  book,  under  their  proper  headings, 
but  the  types  I  will  describe  at  this  time,  although 
they  may  be  similar  in  some  respects  to  the  others, 
are  decidedly  ranked  as  standard  equipment. 

Drill  Ghndoi  and  Sodcets.— Beferring  to  Figure  56, 
the  drill  socket,  A,  is  tapered  on  the  outside  to  fit 
the  spindle  of  the  drill  press,  and  the  tang,  B,  acts 
as  a  driver.  A  taper  shank"  drill  is  used  in  a 
socket  of  this  kind,  the  tang  of  the  drill  being  driven 
into  the  slot,  C.  These  sockets  form  a  part  of  the 
equipment  of  any  tool  crib.  They  are  made  up  in 
various  standard  sizes  for  different  kinds  of  tapers. 
These  tapers  are  slightly  different  for  various  ma 
chines,  and  are  known  as  Morse  taper.  Brown  & 
Sharpe,  Jarno^  etc.  They  are  designated  by  number 
and  name,  and  are  all  slightly  different,  both  in  sizes 
and  also  in  the  angle  of  the  taper.  For  instance, 
if  a  drill  press,  having  a  No.  4  Morse  taper  hole  iB 
the  spindle,  is  to  use  a  comparatively  small  drill  hav- 
ing a  tapered  shank  of  No.  2  Morse  taper,  a  socket 
having  a  No.  4  taper  outside  and  a  No,  2  taper  inmi^ 


MACHINE  EQUIPMENT  121 


HG.  56.    DRUiL  CHUCKS,  SOCKBTS,  AND  TAPPIN0  ATTACHMEN1B 


would  be  selected.  The  No.  4  taper  would  fit  the 
spmdle  of  the  machine  and  the  inside  of 'the  socket 
would  fit  the  shank  of  the  drill  to  meet  the  condition 
required. 

An  excellent  socket  for  drill  press  use  possessing 
many  advantages  is  shown  at  D,  Figure  56.  This  is 
known  by  the  trade  name,  magic  chuck,"  and  is 
n»ade  by  the  Modern  Tool  Co.  When  a  number  of 
sizes  of  drills  or  other  tools  are  to  be  used  in  succes- 
sion  in  manufacturing  work,  a  socket  of  this  kind  is 
extremely  valuable,  for  tools  can  be  changed  with 


TOOLS  AND  PATTERNS 


great  facility  while  the  machine  is  miming.  The 
socket  proper  has  a  tang  that  fits  the  spindle  of  the 
drill  press.  On  the  outside  of  the  socket  a  sliding 
sleeve,  E,  fits  loosely  and  is  prevented  from  dropping 
off  by  the  small  retainer,  F,  which  rests  in  a  groove 
cut  around  the  chuck.  The  lower  part  of  the  slidmg 
sleeve  is  bored  out  to  the  diameter  of  the  two  steel 
balls,  G,  lying  normally  in  opposite  drilled  holes  m 
the  chuck.  A  special  form  of  adapter  for  the  drill, 
shown  at  H,  has  a  tapered  hole  and  a  slot  in  the  end 
for  driving  the  tang  of  the  drill. 

The  action  of  the  chuck  when  in  use  is  as  follows: 
The  operator  has  the  tool— drill  or  other  tool— in  its 
socket  but  not  in  the  chuck  proper.  In  order  to  place 
it  in  position  while  the  spindle  is  revolving,  he  grasps 
the  sleeve,  E,  and  lifts  it  with  his  left  hand.  This 
allows  the  balls,  G,  freedom  to  mn  out  into  the  an- 
nular groove,  K,  so  that  the  socket,  H,  can  be  pushed 
up  into  the  hole.  When  the  socket  is  pushed  in  to 
its  full  depth,  the  sliding  sleeve,  E,  is  released,  and 
the  balls,  G,  are  forced  back  thereby  into  their 
grooves  on  the  outside  of  the  socket  where  they  act 
as  drivers  for  the  tool.  H,  for  instance,  several  holes 
of  different  sizes  are  to  be  made  on  a  one-spindle 
drill  press  and  an  equipment  of  Magic  sockets  is 
available,  it  is  easily  possible  for  an  operator  to 
substitute  one  tool  for  another  and  complete  the  hole 
in  very  short  order  without  stopping  the  machine  dur 
ing  the  process  of  the  work.  Chucks  of  this  kind  are 
very  useful  as  a  part  of  the  tool  crib  equipment. 

When  smaU  drills  of  the  straight  shank  variety  are 
to  be  held,  another  type  of  chuck  is  generally  used. 


MACHINE  IQUIPMBNT 


If  they  are  of  the  smallest  sizes,  not  requiring  any 
great  pressure  to  drive  them,  the  type  of  chuck,  L, 
is  commonly  employed.  This  chuck  consists  of  a 
sleeve,  M,  threaded  to  the  outside  of  the  body  of  the 
tool  and  having  an  inside  tapered  portion  which 
draws  in  on  the  three  jaws,  N.  The  jaws,  in  turn, 
grip  the  drill  and  center  it  at  the  same  time.  A 
chuck  of  this  type  is  very,  common  and  should  be 
found  in  every  tool  crib. 

Another  type  of  chuck  for  drills  which  are  a  Uttle 
heavier  but  have  straight  shanks  is  shown  at  0, 
Figure  56.  This  chuck  is  made  by  the  T.  R.  Almond 
Mfg.  Co.  The  upper  end  fits  a  shank  which  is  tapered 
to  go  into  the  drill  press  spindle.  The  three  jaws,  P, 
are  controlled  and  moved  in  or  out  by  the  action  of 
a  bevel  gear  and  threaded  nut  which  is  operated  by 
a  special  wrench  having  a  bevel  pinion,  Q,  at  the  end. 
This  chuck  also  is  a  very  useful  adjunct  to  the  tool 
crib. 

Tapping  Attachment  for  Drill  Press.— When  it  is 

necessary  to  tap  a  Sole  or  series  of  holes  in  a  piece  of 

work,  and  it  is  desired  to  perform  the  operation  by 

means  of  a  machine  instead  of  by  hand,  a  tapping 

attachment  may  be  used  for  the  work,  applied  to 

a  drill  press  of  the  ordinary  variety.  The  attachment, 

%  Figure  56,  is  made  by  the  Braden  Mfg.  Co.  This 

mechanism  is  so  arranged  that  the  spindle  of  the 

machme,  when  raised  after  the  bottom  of  the  hole 

m  been  reached,  automatically  reverses  the  direction 

01  rotattion  of  the  tap  so  that  it  backs  out  of  the 
wole. 

The  operation  of  the  mechanism  is  as  follows:  The 


12A 


TOOl^  AND  KHrtBBNS 


no.  57.  coiiras  and  chocks 


Bpindle  is  raised  and  lowered  with  the  right  hand 
whUe  the  work  is  inserted  with  the  left  hand,  so  that 
the  operation  of  the  mechanism  is  almost  contmuous 
The  reversing  gears  are  enclosed  in  a  dnstproof  ci^- 
S,  and  need  practically  no  attention.  The  ganginn 
of  the  depth  of  the  lid*  can      takeu  care  ot  d) 


#1 


MACHINE  EQraPMBNT 


125 


means  of  the  adjustable  stop,  T.  Several  mechanisms 
of  this  kind  are  on  the  market,  each  of  which  has 
some  feature  to  prevent  the  breaking  of  taps  and 
also  to  make  it  unnecessary  to  reverse  the  spindle 
of  the  machine  when  in  operation. 

Ooltets  and  CShndB.— Cdlets,  sometimes  known  as 
draw-rn  chucks,  are  used  on  many  types  of  machines. 
Probably  the  use  to  which  they  are  most  often  ap- 
phed  is  in  the  holding  of  bar  stock  on  the  screw- 
machine.   They  are  also  employed  to  a  considerable 
extent  on  toolmakers'  lathes,  bench  lathes,  jewelers' 
lathes,  screw  shavers,  and  the  like.  As  a  part  of  the 
shop  equipment,  however,  their  application'is  gener- 
aUy  to  the  toolmakers'  lathes  and  the  screw  machine 
Several  types  of  collets  are  used  for  these  ma- 
chines but  for  stock  of  smaU  size  the  mechanism  is 
most  frequently  Uke  that  shown  at  A,  Figure  57  In 
ttus  case  the  spindle  is  fitted  with  a  nose  piece,  B 
iavmg  a  tapered  hole  in  the  forward  end.  A  spring 
Sleeve,  C,  is  split  in  several  places  around  the  peri^ 
Phery  in  such  a  way  that  it  will  draw  in  or  contract 
M  rt  IS  pnUed  back  into  the  tapered  end  of  the 
joje  piece    The  method  of  pulling  the  coUet  back 
differs  with  the  machine  to  which  it  is  appUed.  In 
we  case  of  a  bench  lathe  or  toolmaker's  lathe  the 

sSH"  ^  """""^  °P*™*^  *e  end  of  the 
s^*r  I  r^"'.*"*  ^  handwheel.  When  the  device 

mechanism  is  usnaUy  operated  by  means  of  a  handle 
"own  m  the  illustration. 


126 


TOOLS  Amy  PATTERNS 


Several  other  types  of  coEets  are  made  for  work 
of  larger  size,  but  these  are  more  in  the  nature  of 
chucks,  and  the  jaws  of  the  collet  are  loosely  held 
and  have  no  forward  or  backward  movement.  An 
example  of  a  collet  chnck  of  this  kind  is  shown  at  D, 
Figure  57.  In  this  case  the  nose  piece  is  screwed  to 
the  end  of  the  spindle  and  the  jaws,  E,  are  operated 
by  a  closer  which  slides  forward  on  the  tapered  por- 
tion of  the  jaws  when  the  sleeve  indicated  is  pushed 
forward  through  the  spindle.  A  particular  advantage 
of  this  type  of  chuck  is  that  there  is  no  longitudinal 
movement  to  the  jaws  as  they  contract  and  expand. 
They  can  be  used,  therefore,  for  second  operation 
work  (that  is,  work  which  has  previously  been  par- 
tially machined)  with  the  assurance  that  the  longi- 
tudinal positron  will  come  the  same  in  every  case. 

Step  Camcks.— After  a  piece  of  cylindrical  work 
has  been  machined  in  a  previous  operation  and  other 
work  is  to  be  done  on  it  which  will  be  true  with 
that  previously  done,  it  is  frequently  held  by  the 
previously  finished  surface  in  either  a  collet,  such  as 
that  noted  in  the  preceding  illustration,  or  by  means 
of  a  step  chuck  such  as  that  shown  at  F.  Or  an  ex- 
panding arbor  may  be  used  when  the  work  pre- 
viously done  has  consisted  of  boring  and  reaming  a 
central  hole  in  the  piece.  The  step  chuck  principle, 
as  shown  at  F,  is  extremely  useful  for  finishing  woi'k 
of  this  character,  G.  The  step  chuck  body,  H,  is 
operated  by  means  of  a  mechanism  in  the  same  inaB- 
ner  as  the  collet  jaws  previously  mentioned.  Th« 
chuck  itself,  however,  in  this  case  is  made  of  sott 
material,  so  that  it  can  be  machined  to  the  proper 


MACHINE  EQUIPMENT 


127 


size  to  hold  the  work  while  it  is  in  the  machine  on 
wliich  it  is  to  be  used. 

Taking  the  case  shown  as  an  example,  the  method 
of  "stepping  out"  the  chuck  would  be  to  place  a 
piece  of  round  stock  of  small  diameter  in  the  jaws 
and  set  up  the  closing  mechanism.  This  work  would 
be  done  on  the  machine.    While  in  this  condition, 
the  chuck  would  be  bored  out  to  the  diameter  re- 
quired  for  holding  the  blank,  G,  after  which  the 
cylmdrical  piece  would  be  taken  out  of  the  chuck 
which  would  then  be  ready  for  use.   It  will  be  seen 
that  this  mechanism  is  exactly  similar  in  action  to 
the  collet  shown  at  B,  except  that  it  is  of  larger 
diameter  and,  consequently,  has  a  greater  latitude. 

Two-Jawed  Chucks.— Two-jawed  chucks  form  a 
very  useful  part  of  the  machine  equipment,  par- 
ticularly on  small  hand  screw  machines  in  the  hold- 
ing  of  irregular  work  or  pieces  which  cannot  easily 
Je  held  in  m  three-jawed  scroll  chuck.   A  chuck  of 
tins  kmd  is  shown  at  K,  Figure  57,  the  small  end 
being  screwed  directly  to  the  end  of  the  spindle, 
lius  chuck  is  commonly  operated  by  means  of  a 
wrench,  although  various   applications   are  made 
Which  provide  a  means  of  operating  that  is  quicker 
tiian  the  wrench  method.  Sometimes  compressed  air 
operating  on  a  plunger  through  the  spindle  is  used, 
and  at  other  times  a  wedge  or  a  rack-and-pinion  is 
«sed,  depending  on  the  type  of  chuck  and  the  method 
davocated  by  the  manufacturer. 

In  the  type  shown,  the  mechanism  is  controlled  by 
means  of  a  right-  and  left-hand  screw,  L,  which  is 
journaled  at  M  in  the  body  of  the  chuck  in  such 


128 


TOOLS  AND  PATTERNS 


maimer  that  it  has  no  crosswise  movement.  The 
jaws,  0,  are  tongaed  t6  fit  a  slot,  P,  running  across 
the  chuck,  and  the  lower  portion  of  the  jaw  is  tapped 
ont  to  receive  the  body  of  the  right-  and  left-hand 
screw,  L,  previously  mentioned.  It  will  be  seen  that 
as  the  screw  is  operated,  the  jaws  move  in  or  out, 
according  as  the  screw  is  tnmai  to  the  right  or  left. 

Jaws  of  this  kind  are  frequently  provided  with  a 
dovetail  into^  which  sub-jaws,  Q,  can  be  inserted. 
This  is  done  so  that  the  same  chuck  can  be  used  for 
a  number  of  different  pieces  by  simply  making  up  a 
set  of  sub-jaws  or  inserted  jaws  of  the  desired  form. 
'In  tie  instance  shown  in  Figure  57,  the  work,  E, 
which  is  being  held,  is  of  rectangular  form,  and  the 
chuck  is  provided  with  two  locating  plates,  S,  to 
give  the  sidewise  location  while  the  jaws  center  the 
work  in  the  opposite  direction. 

When  a  two-jawed  ehnck  is  to  be  used  for  holding 
an  irregular  piece  of  work,  the  inserted  jaws  are  gen- 
erally formed  to  the  desired  shape,  after  which  they 
are  hardened  and  set  in  place  in  the  chuck.  Jaws 
of  this  kind  are  very  useful  for  small,  irregular 
shaped  forgings  or  castings,  and  also,  when  applied 
to  the  larger  variety  of  chucks,  they  can  be  used  for 
heavier  work  of  irregular  form.  For  example,  a 
lever  having  a  long  hub  and  a  crooked  arm,  could  be 
nicely  held  in  a  two-jawed  chuck,  with  jaws  shaped 
to  fit  the  hub  and  so  arranged  that  the  lever  arm 
would  act  as  a  driver.  Such  jaws  may  also  be 
formed  out  to  a  radius  to  fit  thin  brass  or  bronze 
bushings  which  are  to  be  bored  and  reamed;  when 
formed  in  this  way  the  bushings  can  be  held  so  that 


MACHINl  BQUIPMBNT 


129 


there  is  very  little  distortion  caused  by  excessive 
pressure  in  holding. 

Geared  Scroll  Chuck.— The  ordinary  chuck  used  for 
centering  work  on  either  a  lathe  or  turret  lathe  is  a 
three-jawed  geared  scroll  chuck  of  a  variety  similar 
to  that  shown  at  A,  Figure  58.  Chucks  of  this  kind 
have  an  excellent  centering  action,  as  the  jaws  are 
spaced  at  120  degrees  apart  and  all  are  moved  radi- 
aDy  toward  the  center  with  an  equal  movement. 
This  type  of  chuck  can  be  mounted  on  a  faceplate, 
as  indicated  at  B,  which  is  screwed  to  the  end  of  the 
spindle  of  the  machine,  or  the  chuck  can  be  so  de- 
signed that  it  screws  directly  onto  the  end  of  the 
spindle.  In  either  case  the  internal  mechanism  is  the 
same,  and  is  practically  like  that  shown  in  the  illus- 
tration. An  annular  ring,  called  the  scroll,  lies  in  a 
recess  as  shown  at  C.  This  recess  runs  entirely 
around  the  chuck  and  the  scroll  portion  engages  with 
the  bottom  of  the  three  jaws,  D,  which  are  also 
tongued  on  their  sides  into  radial  slots  in  the  body 
of  the  chuck.  The  face  of  the  jaws  is  tongued  to 
receive  special  jaws  of  different  form,  like  that  shown 
at  E  in  the  figure.  These  jaws  are  fastened  by  the 
two  screws  shown  and  can  be  replaced  by  others  at 
any  time  with  very  litle  trouble  on  the  part  of  the 
operator. 

The  chuck  is  provided  with  three  pinions  of  the 
^evel  type,  F,  which  mesh  with  a  bevel  gear  cut  on 
the  back  of  the  scroll  ring.  When  any  one  of  these 
pinions  is  turned,  by  means  of  a  socket  wrench  pro- 
vided with  the  chuck,  the  scroll,  C,  revolves  in  its 
l>ed  and  carries  the  chuck  jaws  radiaUy  inward  or 


130 


TOOLS  AND  PATTERNS 


outward,  aeeording  as  the  pinion  is  operated  to  the 
right  or  left. 

Air-Operated  Chucks. — The  advantages  of  com- 
pressed air  and  the  many  uses  to  which  it  can  be  ap- 
plied in  the  factory  are  becoming  more  and  more 
appreciated  by  the  progressive  manufacturer.  Some 
years  ago  considerable  interest  was  shown  when  a 
machine-tool  builder  of  international  reputation  de 
signed  and  built  a  very  large  fixture  for  use  in  his 
own  plant,  which  had  a  series  of  clamps  by  means 
of  which  the  work  was  held,  the  clamps  being  oper- 
ated by  compressed  air.  An  additional  refinement 
was  supplied  by  the  designer  in  the  introduction  of  a 
pressure  valve  so  arranged  that  the  amount  of  pres- 
sure applied  to  the  clamp  could  be  adjusted  to  provide 
the  same  amount  of  pressure  under  any  condition. 
As  the  work  was  of  large  size  and  peculiar  shape, 
there  was  danger  of  distortion  if  Tom,  Dick  or  Harry 
were  permitted  to  exercise  his  judgment  in  regard  to 
damping  the  nwk,  but  the  application  of  compresse  I 
air  and  the  pressure  valve  made  the  matter  of  hold- 
ing an  absolutely  safe  proposition. 

In  the  past  few  years  methods  of  chucking  or  hold- 
ing work  on  the  turret  lathe  or  screw  machine  have 
received  a  great  amount  of  attention,  and  the  prin- 
ciple of  holding  by  means  of  compressed  air  has 
been  made  use  of  by  several  manufacturers.  A  very 
successfnl  type  of  air  chuck,  made  in  a  number  of 
varieties  by  the  Hannifton  Mfg.  Co.,  is  shown  at  6, 
Figure  58.  In  the  type  shown  the  jaws  are  three  in 
number,  as  shown  at  H,  and  on  these  jaws  an  adjust- 
able jaw,  K,  Is  mounted.  By  means  of  the  screw,  h 


MACHINE  IQUIPMBNT 


131 


MO.  58.    TMBEE  Ykmsmm  OF  CHUCKS 


these  adjustable  jaws,  K,  can  be  set  in  or  out  in1| 
radial  direction  toward  the  center  of  the  chuck  to 
provide  for  holding  pieces  of  different  diameter,  or 
they  can  be  set  eccentrically  at  different  distances 
from  the  center  to  suit  any  particular  case.   On  the 


TOOLS  AND  PATTERNS 


adjustable  jaws  tbe  work-holding  jaw.  My  is  looated 
by  means  of  the  tongue  shown. 

The  operation  of  the  mechanism  is  as  follows:  The 
chuck  is  slotted  in  three  places  to.  receive  the  oper- 
ating levers,  each  of  these  levers  being  provided 
with  an  arm  whieh  enters  a  slot  iiiM  side  of 
the  jaws,  H.  A  plunger,  0,  runs  back  through  the 
spindle  and  connects  with  the  air  cylinder  at  the  rear 
of  the  spindle.  The  front  end  of  the  plunger  is  so 
grooved  that  it  engages  with  the  three  lever  arms  as 
indicated  at  P.  When  it  is  desired  to  operate  the 
chuck  jaws,  a  conveniently  located  two-way  valve  is 
opened,  allowing  the  air  to  enter  the  cylinder  at  the 
rear  of  the  spndle  and  pull  back  upon  the  plunger, 
0,  which  in  its  turn,  operates  the  lever  arm,  N,  that 
moves  the  jaws  inward  in  a  radial  direction  to  grip 
the  work  firmly.  The  amount  of  pressure  used  can 
be  regulated  by  means  of  a  pressure  valve  if  desired, 
depending  upon  the  work  which  is  to  be  held,  so  that 
a  delicate  pressure  or  a  powerful  clamping  action  can 
be  readUy  obtained. 

Air  chueks  of  this  kind  are  extremely  useful  for 
chucking  work  of  various  kinds  on  turret  lathes  and 
screw  machines,  and  they  can  be  obtained  in  a  num- 
ber of  sizes  and  shapes  to  suit  the  most  fastidious 
customer.  It  is  evident  that  special  jaws  can  be 
adapted  without  difficulty  to  chucks  of  this  kind,  so 
that  they  can  be  made  to  handle  a  variety  of  work. 

Fonr-lttiped  Iiid«p«admi  OhiielL— In  the  course  of 
general  manufacturing,  or  for  work  in  the  tool-room, 
it  happens  occasionally  that  a  piece  of  irregular 
shape  needs  to  be  held.   In  a  case  of  this  kind  the 


MACHINE  EQUIPMENT 


133 


three-jaw  chuck  cannot  be  used  to  advantage  since 
it  is  adapted  only  for  work  which  can  be  centered. 
For  tool-room  work  an  independent  chuck  is  frequently 
used  for  holding  irregular  shapes,  the  workman  set- 
ting up  the  piece  in  the  jaws  approximately  to  the 
center  which  is  to  be  bored  or  drilled  and  then  using 
an  indicator  on  the  work  to  indicate  the  exact  center. 
Such  a  chuck  is  shown  at  Q  in  Figure  58.  It  will  be 
seen  that  this  chuck  is  indispensable  both  in  the 
tool-room  and  for  general  manufacturing  for  holding 
irregularly-shaped  pieces  on  the  turret  lathe  or  on  the 
boring  mill.   When  a  number  of  pieces  of  the  same 
kind  are  to  be  chucked  one  after  the  other,  and  when 
these  pieces  cannot  be  held  by  the  ordinary  three- 
jawed,  geared,  scroll  chuck,  it  is  customary  to  set 
two  of  the  jaws,  or  more  if  possible,  to  the  proper 
center  to  act  as  a  vee  in  locating  the  teeth.  The 
work  is  then  placed  in  the  chuck  with  the  proper  sur- 
faces  against  the  two  fixed  jaws,  and  the  other  jaws 
are  brought  up  independently.    The  construction  of 
this  chuck  is  clearly  indicated  in  Figure  58.  The 
jaws  are  moved  radially  by  the  screws,  S,  which  in 
their  turn  are  controlled  by  a  socket  wrench  (not 
shown  in  the  illustration).   The  body  of  the  chuck 
IS  generally  fastened  to  a  faceplate,  as  shown  at  T, 
which  is  screwed  to  the  nose  of  the  spindle.  The 
lace  of  the  jaw  is  provided  with  a  series  of  notches, 
so  that  a  special  jaw  of  any  particular  kind  can  be 
easily  attached  to  it.    As  ordinarily  furnished,  the 
Chuck  IS  supplied  with  one  or  more  sets  of  jaws 
stepped  out  at  different  diameters,  so  that  a  variety 
01  work  can  be  held  without  recourse  to  special  jaws. 


lU  TOOm  AND  PATfllMS 


lH}.  59.   MAinirACTUBEMO  JkND  IIACHIHE  VinS 


Machine  and  Manufacturing  Vises.— The  impor- 
tance of  the  proper  way  of  holding  a  piece  of  work 
to  be  inachined  cannot  be  overestimated.  Hence, 
vises  are  nsed  on  many  classes  of  machines  for  hold- 
ing work  during  the  process  of  machining.  They  are 
particularly  useful  on  the  milling  machine  and  the 
drill  press;  and  recent  developments  along  these 
lines  have  developed  a  particular  type  of  vise  called 
a  manufacturer's  vise.  This  vise  is  more  or  less 
adaptable,  and  suitable  stops  can  be  applied  and 
locating  pins  put  in  for  the  purpose  of  locating  a 


MACHIHE  EQUIPMENT 


135 


small  number  of  pieces  and  holding  them  securely. 
Attachments  provide  for  drill  bushings  of  different 
sizes,  and  drill  plates  to  hold  the  bushings  can  be 
applied  with  little  trouble.  The  Graham  Manufac- 
turmg  Co.  makes  a  useful  tool  of  this  kind,  as  shown 
at  A,  B,  and  C,  Figure  59.  The  upper  figure,  A, 
shows  the  vise  supplied  with  special  jaws,  D,  and  a 
drill  plate  of  an  adjustable  type,  E,  which  can  be 
moved  to  any  desired  location  over  a  piece  of  work 
held  in  the  vise  jaws.  The  figure,  B,  shows  another 
plate  applied  to  the  same  type  of  vise;  the  work,  F, 
is  held  between  the  vise  jaws  and  obtains  its  endwise 
bcation  against  the  stop,  G,  which  is  likewise  adjust- 
able. A  third  application  of  this  vise  is  shown  at  C, 
where  a  set  of  special  jaws  of  V-type  are  used  to 
center  a  piece  of  round  work,  and  the  drill  plate  is 
set  centrally  so  that  the  vise  can  be  used  as  a  cen- 
tering jig. 

An  excellent  type  of  machine  vise  employing  a  cam 
as  the  locking  principle  is  shown  at  H,  Figure  59. 
This  vise,  made  by  the  F.  C.  Sanford  Manufacturing 
Co.,  IS  an  excellent  example.  It  can  be  used  as  an 
ordinary  vise  and  adapted  to  special  conditions  with 
standard  jaws,  as  shown  at  K,  or  these  jaws  can  be 
made  up  in  special  form  to  suit  particular  cases. 
Approximate  location  of  the  jaws  is  obtained  by 
means  of  the  screw,  L;  after  the  location  has  been 
obtained  the  entire  locking  movement  is  made  by  the 
ever,  M,  which  is  eccentrically  placed  with  relation 
to  the  link,  N,  by  means  of  which  the  jaw  is  locked, 
^wiufacturing  vises  of  this  type  are  coming  more 
more  into  use  and  several  varieties  are  on  the 


136 


TOOLS  AND  PATTERNS 


American  market.  They  are  made  in  a  number  of 
styles  and  sizes  to  suit  different  conditions. 

The  ordinary  madune  vise  commonly  found  on  the 
milling  machine,  also  nsefnl  in  drill  press  work,  is 
shown  at  0,  Figure  59.  This  type  of  vise  is  operated 
by  a  sliding  jaw,  controlled  by  a  screw  which,  in 
turn,  is  manipulated  .by  the  handle,  P.  This  Yim  is 
made  by  |||||g||g||||  ^  gharpe  Mfg.  Co.,  and  can  be 
provided  with  false  jaws  to  hold  special  forms  of 
worky  as  indicated  at  Q.  A  vise  of  this  sort  is  found 
IB  eTery  tool  crib,  usually  in  several  sizes. 

nip%  Dies,  and  Holdem.— The  ordinary  method  of 
cutting  a  thread  on  the  outside  of  a  single  piece  of 
cylindrical  work  is  to  chase"  it  on  an  engine  lathe 
with  a  single-point  tool,  gearing  up  the  lathe  to  the 
proper  pitch,  or  number  of  threads  per  inch,  and 
taking  several  cuts  successively  upon  it  until  the 
desired  depth  has  been  reached.  When  a  hole  of  odd 
size  is  to  be  threaded  in  a  piece  of  worki  the  same 
method  may  he  employed,  but  the  type  of  tool  used 
is  one  adapted  to  internal  cutting.  Both  procedures 
may  be  used  with  success,  but  they  are  uneconomical 
unless  the  work  is  of  particular  accuracy  and  difficult 
to  get  at  with  some  other  types  of  threading  tools. 
A  properly  equipped  tool  crib  should  be  provided 
with  complete  sets  of  taps,  dies,  chasers,  and  suitable 
holders  for  them,  so  that  any  type  of  standard  thread 
can  be  cut  without  difficulty.  If  the  thread  to  be  cut 
is  difficult  of  access,  the  lathe  method  may  be  the  only 
one  possible. 

Mgure  60  shows,  at  A,  a  standard  type  of  hand 
tap  which  is  commonly  used  in  connection  with  a 


MAOHINIS  EQUIPMENT 


If? 


jia.  60.  TAPS,  mm,  and  houhhs 

wrench,  B,  for  tapping  out  a  hole  by  *'man  power." 
The  tap  itself  is  squared  on  one  end  so  that  it  can 
be  readily  held  in  the  adjustable  jaw,  F,  by  a  turn 
of  the  threaded  handle,  G.  The  same  taps  are  also 
used  in  a  releasing  tap  holder  when  used  on  a  turret 
lathe  or  a  hand  screw  machine.  The  ordinary  type 
of  spring  threading  die^  shown  at  C,  in  the  same 
illustration,  is  commonly  used  in  a  die  holder  such 
as  that  indicated  at  D.  Such  a  die  is  used  for  thread- 
ing screws,  studs,  or  other  eylindrical  work,  either 
by  hand  or  by  a  screw  machine;  the  holder,  D,  being 
used  when  the  work  is  done  by  hand.  A  special  type 
of  holder  is  used  on  the  screw  machine,  which  is  of 
the  releasing  variety  such  as  that  used  for  holding 
a  tap  on  the  same  machine. 

If  the  taps  and  dies  mentioned  are  used  on  a  screw 
niachine  or  turret  lathe,  it  is  necessary  to  reverse 
the  machine  in  order  to  back  off  the  tap  from  the 


TOOLS  AND  PATTERNS 


work  after  the  thread  has  been  cat.   So  also,  the 

spindle  on  the  engine  lathe  must  be  reversed  in  cut- 
ting a  thread  and  the  tool  run  back  out  of  the  way. 
(The  more  modem  varieties  of  engine  lathes  are 
provided  with  a  form  of  indicator  which  makes  a 
reversal  of  the  spindle  unnecessary.)  Naturilljr  a 
considerable  loss  of  time  is  entailed  by  this  oper- 
ation, and  in  order  to  overcome  it  another  type  of 
die  heady  called  an  opening  die,  can  be  used,  whereby 
it  is  unnecessary  to  reverse  the  spindle.  An  opening 
die  of  this  sort,  E,  Figure  60,  is  made  by  the  Geo- 
metric Tool  Co.  It  can  be  supplied  with  chasers,  E, 
which  may  be  made  for  any  form  or  pitch  of  thread 
within  the  capacity  of  the  die  head.  The  chasers 
accurately  fit  slots  cut  to  receive  them  in  the  face  of 
the  die  head,  as  indicated  in  the  illustration. 

In  operation,  when  used  on  a  turret  lathe  or  hand 
screw  machine,  the  shank,  L,  is  held  in  the  turret 
and  the  open  end,  containing  the  chasers,  is  fed  onto 
the  work  until  a  predetermilied  stop  has  been  reached, 
at  which  time  the  chasers  fly  open  and  permit  the 
die  head  to  be  drawn  back  out  of  the  way.  These  die 
heads  are  extremely  useful  in  manufacturing  work. 
Although  their  first  cost  is  high,  the  fact  that  a  single 
size  of  holder  can  be  used  for  many  sizes  and  varieties 
of  threads  by  the  simple  substitution  of  a  different 
set  of  chasers,  makes  it  an  economical  proposition  xa 
ftie  machine  equipment. 


FIXTURES  FOR  PLAIN  AND  STRADDLE 

iflMilNQ 

Nature  and  Variety  of  Fixtures.— The  process  of 
milling  has  taken  the  place  of  planing  to  a  great 
extent  in  the  general  processes  of  interchangeable 
work,  except  in  cases  where  the  size  of  the  piece  is 
too  large  to  be  handled  to  advantage  on  a  milling 
machine,  or  when  the  accuracy  required,  or  the  shape 
of  the  piece  is  such  as  to  make  it  impossible  to  mill 
the  surface.  There  are  a  number  of  different  types 
of  machines  which  are  adapted  to  the  milling  process 
and  it  naturally  follows  that  the  type  of  milling  fixtures 
which  are  used  on  the  various  machines  must  be  so  de- 
signed that  they  will  apply  to  the  particular  type  on 
which  the  work  is  to  be  done.  Thus,  if  a  piece  of 
work  is  to  be  handled  on  a  milling  machine  having  a 
horizontal  spindle,  the  fixture  will  be  so  designed  as 
to  present  the  work  to  the  cutter  revolving  in  the 
same  way  that  a  carriage  wheel  turns.  Or  again,  if 
a  fixture  is  to  be  used  on  a  milling  machine  having  a 
vertical  spindle,  the  fixture  must  be  so  designed  as 
to  present  the  work  to  the  cutter  revolving  in  a  hori- 
zontal plane,  like  a  top. 

The  two  most  important  types  of  nulling  machines 
i^sed  in  manufacturing  are  those  having  a  horizontal 

138 


TOOLS  AND  PATTBBNS 


spindle  and  those  with  a  vertical  spindle.  Variations 
of  these  types  are  found  in  those  that  have  more  than 
one  spindle,  such  as  duplex  machines  and  multiple- 
spindle  machines.  In  the  duplex  type,  the  spindles 
are  opposed  and  can  he  adjusted  towards  each  other 
until  the  ends  of  the  cutters  strike.  The  multiple- 
spindle  machines  have  from  four  to  seven  spindles, 
some  of  whidi  are  arranged  horizontally  and  others 
vertically. 

It  is  evident  that  in  the  design  of  any  milling  fix- 
ture, the  first  point  to  be  taken  into  consideration  is 
the  nature  of  the  work  and  the  material  to  be  cut. 
The  next  point  is  the  type  of  machine  which  is  best 
adapted  to  the  work;  and  the  third  point  is  the 
method  of  holding  the  piece  when  it  is  being  machined. 

Heoesaity  for  Proper  Holding. — The  most  important 
point  in  connection  with  the  design  of  milling  fix- 
tures is  the  proper  holding  of  the  work;  for  it  must 
not  be  distorted  by  the  pressure  of  the  clamp  used 
in  holding  it  in  jdaee  and,  at  the  same  time,  the 
method  of  clamping  must  be  so  rigid  that  there  will 
be  no  possibility  of  chatter"  which  would  result  if 
the  work  were  allowed  to  swing  out  of  position  under 
pressure  of  the  cot.  In  this  matter  of  holding,  the 
ingenuity  of  the  tool  designer  is  the  important  fac- 
tor, also,  the  lift  or  dragging  action  of  the  cutter 
while  it  is  engaged  with  the  work  must  be  considered. 

A  piece  that  has  previously  been  partially  ma- 
chined, with  either  holes,  slots,  or  other  finished  sur- 
faces, will  naturally  require  different  holding  methods 
than  those  used  for  rough  castings  or  forgings.  For 
in  performing  a  second  or  third  operation  on  a  piec« 


FIXTURES  FOR  PLAIN  AND  STRADDLE  MILLING  141 


of  work,  it  is  essential  that  the  location  should  be 
positively  determined  by  one  of  the  finished  surfaces. 
Which  surface  is  to  be  used  as  a  locating  point  must 
be  determined  by  the  nature  of  the  work  and  the 
sequence  of  the  various  operations  upon  it.  Let  us 
assume,  for  instance,  that  a  lever  having  a  boss  at 
each  end  has  been  drilled  and  reamed  at  one  end 
through  the  boss,  and  that  the  other  end  is  to  be 

straddle-milled."  It  is  obvious,  then,  that  in  order 
to  locate  the  piece  properly  so  that  the  second  milled 
surface  on  the  boss  will  be  at  right  angles  to  the  hole, 
the  work  must  be  located  by  a  stud  in  the  hole,  and 
must  be  set  up  on  the  fixture  in  such  a  way  that  the 
damps  will  not  spring  it  out  of  alignment. 

In  work  that  has  not  been  previously  machined  and 
is  still  in  the  rough  state,  the  locating  points  must 
be  so  placed  as  to  center  the  work  in  relation  to  the 
cut  which  is  to  be  taken  for  the  greatest  degree  of 
profit. 

Milling  Fixture  for  a  Connecting  Rod. — ^An  excel- 
lent example  of  a  milling  fixture  designed  to  handle  a 
drop  forging  of  an  automobile  connecting-rod  is  shown 
in  Figure  61,  the  work  Being  shown  at  A,  and  the  sur- 
face which  is  to  be  milled  being  the  small  end-boss,  B. 
In  this  milling  operation,  which  is  called  straddle 
billing,  two  cutters  of  the  side-milling  type,  C,  are 
set  up  on  an  arbor,  D,  and  are  properly  spaced  with 
a  collar  between  them  so  as  to  make  the  distance 
between  the  cutting  edges  of  the  two  cutters  the 
same  width  as  the  thickness  of  the  boss  to  be  milled. 
In  the  example  shown,  the  boss,  B,  is  located  in  a 
^^-block,  E,  the  angular  surfaces  of  which  tend  to 


142 


TOOLS  AND  PATTERNS 


HO.  61.  simpijE  straddle-milung  fixture  fob  a 

CONNECTING  BOD 


center  the  boss  correctly.  The  large  end,  F,  is 
dropped  down  upon  a  locating  pin,  3,  in  the  base  of 
the  fixture,  and  two  side  stops  in  the  form  of  pins, 
H,  are  set  into  the  lug,  K,  which  is  a  part  of  the 
fixture  base.  The  upper  portion  of  this  lug  is  pro- 
vided with  a  set-screw,  L,  which  acts  upon  the  small 
boss,  B,  to  hold  it  firmly  down  in  the  V-Mock.  A 
cam  lever,  M,  works  against  the  side  of  the  connect- 
ing rod  and  throws  the  piece  over  against  the  two 
pins,  H,  which  give  the  work  its  location, 

A  fixture  of  this  kind  may  be  manipulated  very 
rapidly;  the  design  is  extremely  simple  and  can  be 
made  cheaply.  In  addition  to  this,  the  method  of 
holding  the  work  and  supporting  it  under  the  cut  is 
so  rigid  that  there  is  no  likelihood  of  chatter.  Such 
a  fixture  can  be  made  up  to  hold  a  couple  of  pieces 
if  desired,  in  which  case  two  gangs  of  milling  cutters 


FIXTUBBS  FOR  PLAIN  AND  STIABBMS  MMMMQ  MS 


m.  62.  DOIJBLE-STRADDLS:  MUiLING  TDmjRE  FOB  AN  AUTOMOBI^ 

CONNECTING  ROD 


would  be  required.  All  milling  fixtures  are  provided 
with  keys  such  as  those  shown  at  N,  and  are  also 
slotted,  as  at  0,  so  that  they  can  be  held  down  on  the 
table  of  the  milling  machine  by  means  of  T-bolts. 

Straddle  Hilling  Fixture  Working  from  a  Finished 
Surface. — The  connecting-rod  shown  in  Figure*  61  is 
an  excellent  example  of  another  type  of  fixture.  Let 
assume  that  after  the  first  operation  has  been 
done,  a  hole  is  drilled  and  broached  to  size  in  the 
l>oss,  B.  After  this  operation  it  becomes  necessary 
to  mill  the  other  end  of  the  connecting-rod,  using  the 


144 


TOOiiB  AMD  PATf  SBNS 


hole  in  the  smaller  boes  as  a  loeating  point.  In  this 
manner  the  large  boss,  F,  can  be  milled  accurately  at 
right  angles  to  the  hole.  Keferring  to  Figure  62,  the 
method  of  setting  up  for  this  operation  will  be  clearly 
undmtood.  The  plan  view  above  shows  two  connect- 
ing rods,  the  small  bosses  of  which  have  been  milled 
with  holes  drilled  and  broached  in  the  manner  just 
described* 

In  the  first  place,  the  bosses,  B,  in  the  small  end 

have  plugs,  Q,  inserted  in  them  which  snugly  fit  the 
holes.  These  plugs  rest  in  two  pairs  of  V-blocks,  E, 
for  purposes  of  alignment,  and  the  V-blocks  are  fin- 
ished on  the  surfaces,  P,  so  that  the  sidewise  location 
is  assured.  The  other  end  of  the  work  which  is  to  be 
machined  drops  down  upon  the  finished  pad,  B,  on 
the  base  of  the  fixture.  When  the  connecting-rods 
are  to  be  clamped  in  place  on  the  fixture,  the  strap, 
S;  is  placed  across  the  two  rods  and  the  nut,  T,  is 
tightened,  thus  securing  the  work  firmly.  A  coil 
spring,  U,  is  placed  under  the  clamp  in  order  to 
assist  in  raising  it  when  the  work  is  being  removed 
from  the  fixture. 

It  will  be  seen  that  this  method  of  locating  from  a 
finished  hole,  and  also  the  method  of  clamping  with  a 
strap  across  both  pieces,  makes  it  possible  to  set  up 
the  work  without  any  fear  of  distorting  it  or  throw- 
ing it  out  of  alignment.  Fixtures  of  this  kind  are  in 
common  use  on  many  varieties  of  work  and  can  be 
applied  to  other  instances  in  which  the  same  prin- 
ciple is  involved.  Both  of  the  fixtures  shown  in 
Figures  61  and  62  are  adapted  for  use  on  a  horizon- 
tal type  of  milling  maehine. 


FIXTUBBS  FOR  PLAIN  AND  ST 


im  m 


Gang  MilHng.— In  milling  several  surfaces  of  vary- 
ing depths  on  any  piece  of  work,  if  the  production 
is  sufficient  to  warrant  the  work  being  done  in  a 
single  operation  with  a  gang  of  special  cutters,  a 
fixture  should  be  designated  so  that  the  cutters  may  be 
mounted  on  an  arbor  to  obtain  the  proper  spacings 
and  depths.  A  good  example  is  shown  at  A,  Figure 
63. 

In  this  case  the  work  has  several  shoulders  and 
several  plane  surfaces  of  different  heights,  as  shown 
in  the  illustration.  The  milling  fixture  is  of  ex- 
tremely simple  type,  and  is  nothing  more  nor  less 
than  a  cast-iron  block,  B,  grooved  and  finished  at 
C  and  D  to  give  the  proper  location  to  the  work  in 
relation  to  the  table.  A  set-screw,  E,  or  several  set- 
screws,  according  to  the  length  of  the  work,  is  used 
to  clamp  it  against  the  surface,  D.  An  important 
feature  in  the  design  of  any  sort  of  milling  fixture 
in  which  the  work  is  located  against  finished  sur- 
faces, is  the  groove,  F,  the  purpose  of  which  is  to 
allow  any  dirt  or  chips  which  might  accumulate  in 
the  fixture  to  be  swept  out  of  the  way  and  passed 
down  into  the  groove  so  that  they  will  not  interfere 
with  the  location  of  the  work.  The  cutter  gang, 
shown  at  G,  H,  I,  J,  and  K,  is  so  arranged  that  it 
will  give  the  proper  spacing  and  depth.  Many  varie- 
ties of  work  can  be  handled  with  a  set  of  cutters  of 
similar  character  to  these,  and  the  work  can  be  pro- 
duced at  a  rapid  rate  and  within  good  commercial 
limits  of  accuracy. 

End  Milling  a  Slotted  Bracket.— It  is  frequently 
necessary  in  the  process  of  manufacturing  to  cut  a 


146  TOOLS  AND  PATTERNS 


FIG.  63.    MXTURES  FOR  VARIOUS  KINDS  OF  MILLING  OPERATIONS 


slot  in  a  casting  or  forging  which  will  bear  a  certain 
relation  to  some  other  finished  surface.  An  example 
is  shown  in  Mgnre  63  at  L.  In  this  example  the 
bracket,  M,  has  been  previously  machined  at  the  side 
and  base,  and  it  is  now  necessary  to  cut  the  slot,  N, 
in  a  certain  relation  to  these  two  surfaces.  The 
method  of  setting  np  the  work  in  this  ease  is  Terj 


FIXTURES  FOR  PLAIN  AND  STRADDLE  MILLING  147 


simple,  as  the  fixture  itself  consists  of  an  angular 
plate,  0,  which  is  fastened  down  to  the  milling  ma- 
chine table  in  the  usual  manner.  The  work  is  located 
on  the  finished  pad  at  the  base  and  against  the  side 
surface,  being  clamped  in  position  by  means  of  the 
two  bolts  shown.  The  cutter  which  is  used  for  this 
work  is  a  spiral  end  mill,  P,  which  is  clearly  shown 
in  the  fixture.  In  operation,  the  table  feed  of  the 
milling  machine  is  started  and  the  work  is  run  di- 
rectly by  the  cutter  at  the  position  indicated. 

Fixture  for  Angular  Hilling.— Taking  as  an  ex- 
ample the  same  bracket  shown  at  L,  let  us  assume 
that  an  angular  surface,  Q,  is  to  be  miUed  upon  it  in 
another  operation,  bearing  a  certain  relation  to  the 
previously  finished  surfax,^.  A  piece  of  work  of  this 
kind  may  be  handled  in  three  different  ways,  but  in 
order  to  make  the  application  of  the  milling  machine 
more  clearly  apparent,  let  us  assume  that  in  this 
a  horizontal  type  6t  machine  is  used  which  hasVHB 
vertical  milling  attachment  that  can  be  swung  to  any 
desired  angle.  The  procedure  then  would  be  to  set 
over  the  vertical  attachment  to  the  desired  angle  of 
the  finished  surface,  Q,  and  to  locate  the  work  hori- 
zontally as  in  the  preceding  instance,  using  a  type 
of  fixture  shown  at  R,  with  suitable  locaters  and 
clamps.  A  milling  cutter  of  the  spiral  end-mill  type 
is  inserted  in  the  milling  attachment  as  indicated  at 
S,  and  the  machine  table  is  fed  under  the  work  while 
in  the  position  indicated. 

Another  method  of  handling  the  same  piece  of  work 
would  be  to  build  the  fixture  itself  on  an  angle  with 
the  table,  so  that  the  surface,  Q,  which  is  being  milledi 


148 


TOOLS  AND  PATTERNS 


would  lie  parallel  to  the  table  itself.  In  snail  a  case, 
an  ordinary  type  of  plain  milling  cutter  would  be 
used,  the  cutter  having  straight  cutting  edges  parallel 
to  the  surface  of  the  table.  The  work  could  also  be 
performed  in  the  same  fixture  as  that  shown  by 
swinging  the  vertical  milling  attachment  to  another 
angle  and  using  the  end  of  the  mill  for  making  the 
cut,  instead  of  the  side  of  the  mill  as  indicated  in  the 
drawini^. 

Fizlmre  fer  Form  IDIHns:.— Let  it  be  assumed  that 
a  piece  of  work,  T,  is  to  be  formed  to  the  contour 
shown.  The  work  has  been  previously  machined 
along  tiie  base,  but  has  not  been  surfaced  on  the 
edges.  It  is  necessary  to  reduce  the  form  that  is 
parallel  to  the  lower  surface  and  approximately  in 
line  with  the  edges  of  the  work. 

1m  this  ease  the  fixtnra,  Wf  is  of  U-section,  bolted 
to  the  table  in  the  usual  manner,  and  located  by 
means  of  tongues  in  the  table  T-slots.  Two  adjust- 
able studsy  W|  are  furnished  along  the  side,  and 
against  these  stn^  fhe  rough  side  of  the  work  is 
located,  being  clamped  firmly  against  it  by  means  of 
the  thumb-screws,  X.  It  is  customary,  in  work  of 
this  kind,  either  to  build  a  fixture  which  will  take  a 
number  of  pieces  ot  the  same  kind,  or  else  to  make 
the  work  in  a  single  strip  and  cut  it  up  into  pieces 
of  the  desired  length  after  it  has  been  machined. 
Naturally,  the  process  which  is  to  be  used  determines 
the  method  of  holding  and  clamping.  The  formed 
milling  cutters,  Y,  and  side  milling  cutters,  Z,  are 
made  up  to  suit  the  contour  of  the  work  to  be  manu- 
faetmred. 


FIXTURES  FOR  PLAIN  AND  STRADDLE  MILLING  149 


HQ.  64.    DOUBLE  INDEXING  FIXTURE  FOR  STRADDLE  MILUNO 

LEVERS 

Index  MilMng  a  Pair  of  Levers. — ^When  rapid  pro- 
duction is  desired  on  a  piece  of  work  it  may  be  pos- 
sible and  profitable  to  arrange  a  fixture  similar  to 
that  shown  in  Figure  64.  Here  we  have  two  levers 
of  identical  size,  but  the  bosses  on  the  ends  are  of 
two  different  widths.  They  can  be  machined  in  a 
single  setting  by  a  suitable  arrangement  of  the  fix- 
ture and  cutter.  In  the  case  shown  the  levers  have 
a  boss  at  one  end,  as  at  A,  and  at  the  other  end,  as 
at  B.  The  fixture  is  built  so  that  it  will  hold  the  two 
levers  in  such  a  way  that  a  large  and  a  small  end  are 
successively  presented  to  the  cutters  at  A  and  B,  and 
these  cutters  are  spaced  so  as  to  mill  different  widths 
according  to  the  thickness  of  the  bosses. 

The  fixture  locates  the  work  in  each  case  against 
the  small  set-screws,  C,  to  give  sidewise  location 
against  the  sides  of  the  lever,  and  suitable  V-blocks, 
D,  hold  the  bosses  centrally.  The  V-blocks  are  at  one 


TOOLS  AND  PATT£fiNS 


end  only,  the  other  enda  rest  against  the  angular  sur- 
face, £.  ^Ehnmb-serewsy  P,  are  provided  on  each  side 
of  the  fixture  to  hold  the  work  against  the  set-screw, 
C.  A  rocking  clamp,  G,  on  each  of  these  set-screws 
equalizes  any  variation  in  the  forging  and  makes  the 
damping  action  positive.  An  ordinary  strap  clamp, 
H,  holds  the  work  down  on  the  fixture. 

The  method  of  using  the  fixture  is  to  mount  it  suit- 
ably on  a  base,  such  as  that  shown  at  K,  centering  it 
by  means  of  a  central  -jpiugf  L.  The  base  is  fastened 
down  to  the  table  of  the  milling  machine,  but  the 
upper  portion,  M,  can  be  swung  around  through  an 
arc  of  180  degrees  so  as  to  present  the  opposite  ends 
of  the  levers  to  the  cuttero  in  sequence.  Indexing  is 
usually  performed  manually  by  the  operator  with 
some  type  of  locating  pin  which  gives  the  correct 
location  when  indexing  from  one  position  to  another. 
A  scheme  for  accurately  indexing  a  piece  of  this  kind 
will  be  described  under  the  next  heading.  The  fore- 
guing  fixture  mills  two  ends  of  two  bosses  at  the 
same  time  and  is  then  indexed  to  mill  the  two  oppo- 
site ends,  so  that  four  ends  of  the  two  levers  have 
been  machined  at  a  single  setting.  But  it  must  be 
recalled  that  a  fixture  of  this  kind  is  not  economical 
unless  a  number  of  pieces  are  to  be  machined. 

Indttx  WSOing  nxtane  for  Quantity  Production.->In 
work  that  is  being  put  through  a  shop  on  the  inter- 
changeable system,  as  in  automobile  production  or 
other  manufacturing  where  a  number  of  pieces  of  the 
same  sort  are  to  be  successively  machined  to  a  given 
size,  a  number  of  pieces  are  usually  found  which  re- 
quire some  sort  of  an  indexing  fixture  for  milling 


mXTWMB  FOB  FliAIN  AND  STBADB]j£  MlMilNa  151 


  j/^imf  ■       

VIO.  65.    SUIHJS  INDBX-lfUlINO  WiXTU«E 


slots,  clutch  teeth,  and  the  like.  The  progressive  de* 
signer  of  tools,  therefore,  usually  designs  some  sort 
of  universal  milling  fixture  which  has  sufficient  flexi- 
bility that  it  can  be  adapted  to  such  a  variety  of 
work. 

For  example,  while  supervising  the  work  on  a  large 
automobile  plant  equipment  for  a  Eussian  corpora- 
tion, I  used  recently  the  type  of  fixture  shown  in 
Figure  65  over  twenty  times  on  as  many  differ^t 
cases.  The  indexing  mechanism  and  the  base  of  the 
fixture  were  practically  the  same  in  every  case;  the 
only  differences  were  in  the  number  of  points  of  in- 
dexing and  in  the  adapters  which  were  used  to  hold 
the  different  shapes  to  be  milled.  A  particular  ad- 
vantage in  this  type  of  fixture  is  its  adaptability  to 
^Ufferent  conditions,  and  also  to  the  fact  that  it  is 

practically  impossible  to  destroy  the  correct  indexing 


152        .         TOOLS  AND  PATTERNS 

of  the  fixture,  as  the  mechanism  is  so  well  protected 
from  chips  and  dirt  that  no  trouble  can  be  caused 
thereby.  As  this  fixture  is  so  notably  flexible,  it  is 
worth  while  to  describe  it  in  greater  detail  than 
might  otherwise  be  deemel  necessary. 

The  base  of  the  fixture,  A,  is  fastened  to  the  milling 
machine  table  by  the  bolts  shown,  being  located  in 
the  usual  manner  by  keys  in  the  table  T-slot.  A 
revolving  table,  B,  is  suitably  mounted  on  a  stud,  C, 
IE  the  center  of  the  base.   On  the  under  side  of  the 
table  a  hardened  tool-steel  indexing  ring,  E,  is  se- 
curely fastened  by  means  of  screws,  and  is  provided 
with  angular  slots,  F,  around  its  periphery,  as  many 
in  number  as  the  indexing  points  which  are  to  be 
made.  A  sliding  block,  G,  is  located  radially  in  rela- 
tion to  the  index  plate  and-  is  tapered  on  the  end 
which  fits  the  angular  slot  in  the  index  plate,  thus 
determining  the  radial  indexing  points  on  the  fixture. 
The  movement  of  this  sliding  block  is  controlled  by 
a  handle,  H,  and  it  is  drawn  back  into  position  by 
the  spring,  K,  when  the  proper  indexing  point  has 
been  reached.  It  will  be  seen  that  the  location  of  the 
slots  in  the  index  plate  is  such  that  it  is  practically 
impossible  for  any  chips  or  dirt  to  interfere  with 
the  proper  location  of  the  table.    The  upper  part 
of  the  fixture  can  be  fitted  with  adapters  of  liferent 
kinds  to  hold  various  shapes  or  forms  which  are  to 
be  milled. 

The  work  shown  in  the  illustration  is  a  cylindrical 
piece,  L,  which  is  squared  up  at  the  upper  end  by  the 
two  milling  cutters,  M.  This  piece  of  work  is  located 
on  a  spring  stud,  N,  expanded  by  means  of  the  bolt, 


HXTUBBS  FOB  PLAIN  AND  STRADDLE  MILLING  153 


0,  SO  that  all  chance  of  vibration  is  taken  up  and 
there  is  no  possibility  of  chatter  during  the  progress 
of  the  work.  A  hand  lever,  P,  is  provided  on  the 
table  to  index  it  from  one  position  to  the  other;  but 
this  feature  is  unnecessary  in  many  cases  as  the 
workman  can  use  the  work  as  a  lever  for  indexing 
the  table.  However,  a  series  of  holes  around  the  per- 
iphery of  the  table  allow  the  pin  to  be  inserted  at 
different  points  to  provide  for  a  circular  indexing 
movement  when  needed.  This  type  of  fixture  is  prob- 
ably one  of  the  most  useful  that  can  be  made  to 
handle  a  great  variety  of  work,  and  although  its  first 
cost  is  fairly  high  it  should  not  by  any  means  be  con- 
sidered an  expensive  fixture. 


C/JHAPTBR  XI 


MXTOKES  FOB  CONTINUOUS  MILLING 

The  Value  of  Simplicity.— It  is  an  eeoBomical 
propositiciiiy  when  a  great  nmnber  of  pieces  of  the 
same  kind  are  to  be  machined  by  the  process  of  mill- 
ing, to  make  the  fixtures  wherever  possible  in  such  a 
way  that  there  will  be  as  little  lost  time  as  possible 
eansed  by  taking  ont  and  pntting  in  the  woA.  It  is 
most  advantageous  to  arrange  a  milling  fixture  in 
such  a  way  that  the  cutters  will  be  working  as  nearly 
continuously  as  possible.  Several  methods  ean  be 
employed,  depending  upon  the  class  of  work  to  be 
done  and  the  machine  which  is  used  for  the  work. 
On  the  regular  type  of  horizontal  milling  machine 
some  classes  of  work  can  be  handled  in  an  almost 
continnons  manner;  although  the  cutting  action  will 
not  be  absolutely  continuous,  there  is  very  little  lost 
time  between  cuts  and  it  is  unnecessary  to  stop  the 
machine  at  any  time. 

A  special  type  of  milling  machine,  called  a  con- 
tinuous miller,  is  made  by  the  Becker  Milling  Ma- 
chine Company.  This  machine  uses  a  revolving  table 
and  a  series  of  fixtnres  arranged  radially  on  the  table. 
The  Potter  and  Johnston  Company  also  make  a  con- 
tinuous milling  machine  having  an  indexing  table  on 
which  the  work  can  be  set  up  on  one  side  of  the  table 

1S4 


FIXTURES  FOE  CONTINUOUS  MIMiINO  155 


TO.  66.    SIMPLE  TYPE  OP  CONTINUOUS  MILLING  FIXTURE 


while  another  piece  is  being  machined  on  the-  oppo- 
site side.  The  Beaman  and  Smith  Company  make  a 
large  machine  with  seven  spindles  which  can  be  used 
for  continuous  milling  on  large  work.  These  various 
machines  require  somewhat  different  types  of  fixtures 
because  of  their  different  arrangement  of  spindles. 

In  selecting  the  simplest  of  continuous  milling  fix- 
tures, let  us  look  at  the  one  shown  in  Figure  66, 
which  is  made  for  a  horizontal  milling  machine.  The 
work  in  this  case  is  a  bracket,  A,  shown  in  the  upper 
part  of  the  illustration.  '  The  bracket  is  to  be  straddle 
milled  by  a  gang  of  cutters,  as  shown  at  B,  which 
are  used  to  face  the  sides  of  the  bosses  as  indicated 
in  the  upper  part  of  the  illustration.  The  fixture  base, 
G,  is  located  on  the  table  of  the  milling  machine  in 
the  usual  manner  and  has  at  each  end  a  simple  type 

of  locating  and  clamping  device  in  which  the  work 


156 


TOOLS  AND  PATTERNS 


is  located  and  held.  A  sectional  view  of  the  arrange- 
ment is  shown  at  the  left-hand  pfortion  of  the  figure. 
The  other  end  is  identical  with  it.  The  work  is 
placed  in  the  position  shown,  resting  against  the  stop 
pins,  D,  and  is  clamped  in  place  by  means  of  the 
screw,  E,  at  the  top  of  the  fixture  and  by  the  clamp, 
F,  at  the  bottom.  The  latter  clamp  is  operated  by 
means  of  the  thumb  nut,  G,  and  is  released  by  the 
coil  spring,  H. 

In  operation,  the  work  is  placed  in  position  and 
clamped  on  one  side  of  the  fixture;  the  table  is  then 
moved  inward  close  to  the  revolving  cutter,  and  the 
feed  is  set  in  operation.  While  the  table  is  moving 
forward  and  the  peee  in  position  is  being  milled,  the 
operator  places  another  piece  of  work  in  position  and 
clamps  it  at  the  other  end  of  the  fixture.  Then,  after 
the  work  at  one  end  has  been  completed,  the  table  is 
moved  over  to  machine  the  other  piece;  the  first  piece 
Is  removed  from  the  fixture  and  another  one  is  in- 
serted in  its  place.  By  this  description  it  will  be 
seen  that  the  process  of  milling  is  nearly  continuous, 
and  for  certain  classes  of  work  this  fixture  can  be 
used  to  good  advantage. 

Continuous  Milling  Fixture  for  Cfylinders.— The 
Beaman  &  Snuth  coBtinuous  milling  machine  makes 
possible  the  machining  of  surfaces  of  large  size  in 
such  a  way  that  the  action  of  the  cutters  with  prop- 
erly designed  fixtures,  is  practically  continuous  from 
the  time  the  machine  starts  in  the  morning  until  the 
factory  closes  at  night.  The  construction  of  the 
machine  is  such  that  there  are  a  number  of  tables 
similar  to,  but  somewhat  shorter  than,  a  planer 


FIXTURES  FOB  OONTINIJOUiilMWG  ISf 


MO.  67.    CONTINUOUS  MJIUNQ  FIXTURE  FOR  AUTOMOBILE 

CYLINDERS 


table,  and  each  of  these  tables  can  be  equipped  with 
a  similar  set  of  fixtures.  These  fixtures  can  be 
loaded  one  after  the  other  and  placed  in  engage- 
ment with  the  feed  mechanism  of  the  table,  one  fix- 
tare  following  the  other  closely  with  very  little  space 
between.  The  fixtures  pass  through  the  machine 
from  one  end  to  the  other,  the  finished  work  is  then 
taken  off  and  is  replaced  by  other  pieces,  after  which 
the  entire  table  with  the  fixtures  mounted  on  it  is 
carried  around  to  the  original  starting  point  and 
started  again  on  its  journey  through  the  machine. 
For  some  classes  of  work  four  or  five  of  these  tables 
w»ay  be  required,  each  with  the  same  type  of  fixture 
^Pon  it.  In  milling  the  cylinders,  transmission  cases, 
and  crank  cases  of  automobiles,  as  well  as  in  other 


TOOLS  AND  PATTERNS 


wofk  of  similiiir  characteri  the  production  wMeh  can 
be  obtained  from  a  macMne  of  this  kind  is  extremely 
high.  Under  favorable  circumstances  from  300  to  400 
automobile  cylinders  of  4^-inch  bore  can  be  produced 
in  a  ten-hour  day. 

A  good  example  of  a  continuous  milling  fixture 
for  automobile  cylinders  is  shown  in  Figure  67.  The 
cylinders,  A,  are  to  be  milled  on  the  surfaces,  B  and 
C.  They  ha¥e  been  previously  machined  on  the  end 
and  in  the  bore.  The  cylinders  are  located  on 
plugs,  E,  shown  dotted  in  the  bore  of  the  cylinder. 
Each  fixture  is  capable  of  holding  six  cylinders  at 
one  time.  The  fixtures  are  held  down  on  the  table 
by  means  of  clamps  and  T-bolts  in  the  T-slots,  and 
the  work  is  held  down  on  the  fixture  by  means  of 
the  clamps  shown  at  F  and  G.  In  the  case  shown 
two  milling  cutters  operate  on  the  u]^r  part  of  the 
cylinders  and  two  more  opposed  to  each  other  are 
used  to  machine  the  surfaces  on  the  sides. 

Fixtaro  for  ''Becker"  Continuous  Milling  Machine. 
—The  Becker  type  of  continuous  milling  machine  uses 
a  revolving  table  which  is  in  continuous  operation 
after  the  first  pieces  have  been  set  in  place  on  the 
fixture.  The  fixture,  shown  in  Figure  68,  is  built 
to  accommodate  twelve  wall  bearings,  as  seen  at  A. 
These  bearings  are  located  in  position  by  the  fixed 
studs,  B,  which  act  as  a  vee,  into  which  the  pieces 
are  forced  by  means  of  the  sliding  V-block,  C,  oper- 
ated by  the  thumb-screw,  D. 

After  the  first  pieces  have  been  placed  in  the  fix- 
ture, the  operator  simply  removes  the  finished  work 
and  continues  to  place  new  pieces  in  the  position 


PIXf  CUES  FOB  OONTINUOUS  MIMiINQ  im 


m.  68.  ooimNuoiis  icnuKo  iixTtjRB  for  bsckee  muuhq 


occupied  by  those  just  finished.  It  will  be  seen  that 
as  the  cutter,  F,  is  in  continuous  movement,  it  has  a 
contact  with  several  pieces  at  the  same  time.  In  the 
case  illu»trated  the  work  is  of  such  nature  that  there 

• 

IS  very  little  "dead  time,"  or  time  when  the  cutter 
^  not  in  contact  with  the  work.  This  example,  there- 
fore, is  an  excellent  one  to  show  the  value  of  con- 
tinuous milling  and  how  it  can  be  applied  to  manu- 


160 


TOOLS  AND  PATTEBNS 


faetnring  work.  However,  when  the  shape  of  a  piece 
of  work  is  such  that  it  cannot  be  set  up  on  a  cir- 
cular fixture  without  leaving  wide  spaces  between 
the  pieces,  it  is  not  advisable  to  attempt  to  mill  it 
by  the  eontinnons  milling  process;  but  with  work 
that  can  be  set  close  together,  it  is  usually  highly 
profitable. 

Spline-Milling  .Fixtures. — Some  years  ago  the  cus- 
tomary method  of  ^tting  a  slot  in  a  shaft  for  a  key- 
wav  was  to  drill  a  hole  at  each  end  of  the  slot  and 
then  mill  from  one  hole  to  the  other.  This  process,  nec- 
essarily, was  somewhat  slow,  and  it  has  been  largely 
replaced  by  seme  form  of  spline-milling  machine  or  a 
spline-milling  attachment  applied  to  a  plain  milling 
machine. 

The  machine  that  is  manufactured  by  the  Pratt 
ft  Whitney  Co.  for  this  purpose  consists  of  two 
opposing  spindles  arranged  in  such  a  way  that  they 
feed  automatically  towards  each  other  during  the 
process  of  the  work.  The  table  is  reciprocated,  with 
the  work  in  position  on  it,  to  a  specified  length  of 
stroke  determined  by  the  length  of  the  key-slot.  The 
fixtures  used  for  this  machine  may  be  those  which 
hold  a  single  piece  for  cutting  two  slots  opposite 
to  each  other,  or  it  may  be  arranged  to  hold  several 
pieces  in  which  one  or  more  slots  are  to  be  cut. 

Spline-milling  machines  are  well  adapted  for  all 
kinds  of  rectangular  key  slotting,  unless  the  work 
to  be  done  is  of  such  a  size  as  to  be  prohibitory.  For 
all  kinds  of  shafting,  arbors,  and  similar  work,  it 
can  be  arranged  without  the  necessity  for  any  elab- 
orate fixture.   In  some  cases,  however,  in  order  to 


FIXTUEfiS  mm  CONTINUOUS  MIIiIiINO  lil 


mo.  69.    DOUBLE  SPUNE-KILLINO  MXTXIBE 

increase  production,  fixtures  may  be  made  to  suit 
particular  cases. 

A  spline-milling  attachment  for  a  hand-milling 
machine,  made  by  the  Standard  Engineering  Co.  to 
^PPly  to  one  of  their  hand  milling  machines,  is  also 
very  useful  for  milling  key-slots,  although  but  one 
cutter  is  used  at  a  time.  The  attachment  is  pro- 
vided with  automatic  features  which  make  it  val- 
uable for  many  kinds  of  manufacturing.  In  the  at- 
tachment mentioned,  the  spindle  is  vertical  in  rela- 
tion to  the  table  of  the  machine.  On  the  spline- 
DTiilling  machine,  however,  the  two  spindles  lie  in  a 
liorizontal  plane. 

Let  it  be  supposed  that  a  piece  of  work,  such  as 
that  shown  at  A,  Figure  09,  is  to  be  splined  or  cut 


tooijS  and  patterns 


011  tlie  mA  with  four  keyways,  as  indieated  at  B  in 
the  end  view.  This  piece  having  the  four  slots  at  90 
degrees  apart  on  the  periphery,  requires  some  sort 
of  indexing  fixture  in  order  that  the  various  slots 
may  be  ent  in  their  proper  relations  to  each  other. 
The  illustration  shows  the  method  of  holding  used 
for  this  fixture  when  applied  to  a  Pratt  &  Whitney 
spline-milling  machine.  The  fixture  base  is  fastened 
to  the  milling  machine  table  by  means  of  bolts 
through  the  slot,  C,  at  each  end  of  the  fixture,  and  is 
aligned  by  means  of  keys  entering  the  table  T-slot. 
The  method  of  locating  the  work  on  this  fixture  is 
out  of  the  ordinary,  and  is  therefore  worthy  of  a 
detailed  description. 

The  two  shafts,  shown  at  D  and  E,  are  laid  on  the 
finished  surface  of  the  fixture.  They  are  held  by  the 
elamp,  F,  the  angular  portion  of  which  grips  and 
pulls  in  on  the  cylindrical  part  of  each  shaft.  As  the 
clamp  screw  is  set  up,  the  two  shafts  approach  each 
other  until  they  strike  against  the  finished  surfaces 
or  dioulders  on  two  inserted  pieces,  0  and  H,  which 
locate  and  align  the  work.  The  first  cut  on  the  key- 
ways  is  made  with  the  pieces  set  in  the  position 
shown,  after  which  the  clamp  is  released  sufficiently 
to  permit  the  two  shafts  to  be  turned  with  the  slot 
downward.  A  positive  method  of  locating  from  the 
first  slot  which  has  been  cut  is  provided  in  the  bed 
of  the  fixture;  and  as  the  shaft  is  revolved  after  the 
first  cut  and  stands  with  the  slot  downward  on  the 
fixture,  this  locater  engages  with  the  slot  and  gives 
positive  location.  The  locaters  are  controlled  by  the 
set^serews,  L. 


MXTUBSS  FOB  CONTINUOUS  miJBBB  163 


It  will  be  seen  that  a  repetition  of  the  indexing 
process  will  produce  the  four  slots  at  90  degrees 
from  each  other  without  the  need  of  expensive  fix- 
tures ordinarily  used  for  this  work.  Other  examples 
of  spline-milling  fixtures  will  be  given,  but  as  they 
are  usually  of  a  simple  form  which  can  be  made  up 
at  minimum  expense,  it  is  unnecessary  to  go  into  the 
matter  more  completely  here. 


CHAPTER  XII 


FACE-PLATE  FIXTURES 

JljttiiiMi  for  Singfe  Ptoim— tlie  general  process 
of  manufacturing,  and  also  in  tool-making,  many 
pieces  of  work  to  be  machined  on  an  engine  or  tur- 
ret lathe  cannot  be  satisfactorily  held  in  any  of  the 
Yarions  forms  of  chneks  previously  described.  For 
such  cases  either  a  face-plate  of  standafd  form  is 
nsed,  as  that  shown  in  Figure  70,  or,  if  a  number  of 
pieces  are  to  be  maehinedi  a  special  face-plate  with 
suitable  lugs  and  clamps  may  be  made  up.  When 
required  for  toolmaking,  or  for  a  single  piece  of 
work,  the  standard  style  of  face-plate  in  Figure  70 
is  commonly  employed.  This  type  is  made  of  cast 
iron  and  is  screwed  to  the  end  of  the  spindle  of  the 
machine. 

If  the  toolmaker  has  a  certain  piece  of  work  to 
bore,  and  the  work  is  of  such  size  that  it  can  be 
clamped  upon  the  face-plate,  he  would  set  up  the 
work  against  the  face  of  the  plate,  A,  and  apply 
suitable  clamps  through  several  of  the  slotted  holes,  B, 
so  that  the  work  could  be  held  in  the  desired  posi- 
tion for  machining  the  hole.  In  setting  up  a  piece 
of  work  of  this  kind  he  would  use  an  indicator  on 
the  work  to  determine  when  it  was  in  the  correct 
position  for  machining.  The  T-dlotSi  C,  em  be  used 

m 


FACE-PLATi;  FIXTUBMS 


165 


Y 


c 


m.  70.  mmBAXD  wace  plate  wm  ah  mmm  lathe 
both  to  hold  the  work  and  to  fix  steel  blocks  in  cer- 
tain locations  on  the  face  of  the  plate  when  several 
pieces  of  the  same  kind  are  to  be  machined.  Such 
a  face-plate  is  seldom  used  in  general  manufacturing 
except  for  the  work  just  described. 

Fixtures  for  Quantity  Production.— We  now  come 
to  the  class  of  manufacturing  known  as  quantity  pro- 
duction, where  many  pieces  of  the  same  kind  are 
produced.  If  a  number  of  pieces  are  to  be  machined, 
it  is  obvious  that  the  face-plate  fixtures  to  be  used 
can  be  made  up  with  quick  clamping  attachments 
which  require  a  minimum  amount  of  time  and  labor 
to  set  up.  They  can  also  be  made  with  simple  clamp- 
ing arrangements  which  answer  every  purpose  for 
holding  the  work  but  which  take  a  little  longer  in 
setting  up.  The  latter  fixtures  are,  of  course,  some- 
what cheaper  than  the  more  elaborate,  and  if  the 
output  is  to  be  comparatively  low,  they  will  answer 
every  purpose. 


TOOLS  AND  PATT£ENH 


no.  71.  TWO  muptM  fage-flatb  fixtubis 


The  fixture.  A,  Figure  71,  is  sbown  holding  the 
work,  B,  a  flanged  collar  which  has  pre¥ionsly  been 
machined  on  its  inside  surface,  C.  As  it  is  neces- 
sary to  cut  out  the  recessed  portion,  D,  of  the  collar 
in  a  subsequent  operation,  the  work  is  located  on  the 
stud,  E,  and  is  clamped  in  place  on  the  locating  stud 
against  the  face  of  the  fixture  by  means  of  the 
clamps,  F,  three  in  number  arranged  equidistantly 
on  the  face  of  the  plate.  In  a  fixture  of  this  kind 
the  revolution  of  the  work  around  the  axis  of  the 
spindle,  G,  is  perfectly  true,  so  that  when  the  recess, 
D,  is  cut  it  will  be  concentric  with  the  previously 
machined  surface,  C. 

Fixtures  for  Cutting  Packing  Bings.— The  other 
example  of  a  face-plate  fixture,  H,  Figure  71,  is  de- 
signed to  handle  a  nng  pot,  K,  from  which  packing 
rings  are  to  be  cut  The  ring  pot  has  previously 
been  faced  on  the  end  shown  against  the  face-plate 
and  three  holes  have  been  drilled  in  the  flange  for 
locating  and  driving  purposes.   The  work  is  set  up 


FACE-PLATE  FIXTURES 


167 


on  the  face-plate  fixture,  locating  on  the  pins,  L,  one 
of  which  is  shown  in  the  illustration.  The  work  is 
clamped  back  against  the  face  of  the  fixture  by  means 
of  three  hook  bolts,  M,  having  an  angular  end  which 
engages  with  the  angular  flange  at  N,  thus  holding 
the  work  back  firmly  against  the  face  of  the  plate. 
This  face-plate  is  provided  with  a  bushing,  O,  in 
which  the  pilot,  P,  of  the  boring  bar  is  guided.  The 
boring  bar  is  used  to  bore  out  the  inside  of  the  pot, 
as  indicated.  When  a  number  of  packing  rings  are 
to  be  made  up  a  fixture  of  this  kind  can  be  used  to 
advantage  or  the  flange  of  the  pot  can  be  made  so 
that  it  can  be  gripped  in  chuck  jaws  of  special  form. 
The  latter  method  is  more  common  at  present  and  is 
superior  to  that  shown,  due  to  the  fact  that  no  pre- 
liminary operation  is  necesary  on  the  work  before 
this  machining  operation. 

Face-Plate  Fixture  for  a  Hub  Plange.— The  face- 
plate  fixture  shown  in  Figure  72  is  somewhat  similar 
to  that  noted  at  A,  in  Figure  71;  but  in  this  case 
the  work  is  located  by  an  outside  surface  which  also 
has  been  previously  machined,  shown  at  A  in  this 
illustration.  The  face-plate,  B,  is  screwed  to  the  end 
of  the  spindle  as  indicated,  and  is  recessed  to  allow 
the  shoulder.  A,  to  fit  into  it,  thus  giving  the  correct 
location.  The  flange,  C,  has  been  drilled  in  several 
places,  as  indicated  at  D,  and  these  drilled  holes  are 
used  for  driving  against  the  pressure  of  the  cut,  by 
means  of  the  pins  indicated.  The  clamps,  E,  three 
in  number,  hold  the  work  back  against  the  face  of 
the  plate,  and  are  slotted  to  allow  them  to  be  drawn 
off  the  flange  when  setting  or  removing  the  work 


168 


TOOLS  AND  PATTERNS 


m.  72.    FAGE-PIATE  FIXTURE  FOR  A  HUB  FLANGE 


from  the  fixture.  The  coiled  springs,  F,  are  pro- 
vided in  order  that  the  clamps  will  always  stand 
away  from  the  work  when  it  is  being  placed  in  position. 
Fixtures  of  this  kind,  largely  used  in  the  general 
process  of  manufacture,  can  be  adapted  to  many 
kinds  of  turret  lathe  work. 

Self-Oentering  Fixture  for  a  Rough  Casting.— It  is 
sometimes  desirable  to  machine  a  piece  of  work,  a 
ring  pot,  for  instance,  whose,  shape  is  such  that  it 
is  not  readily  held  in  chuck  jaws.  A  fixture  for  this 
purpose  is  shown  at  A,  Figure  73.  The  casting,  B, 
is  somewhat  thin  in  section,  and  is  to  be  bored  and 
turned  by  means  of  the  tools,  C  and  D.  As  no 
previous  machining  has  been  done  on  the  casting,  it 
is  necessary  to  center  it  from  the  rough  surface  in 
some  way  and  to  clamp  it  firmly  on  the  fixture. 

For  the  purpose  of  centering  the  work,  a  spring 
tapered  plug,  E,  is  located  in  the  fixture  in  such  a 


FAGE-PLATE  FIXTURES 


169 


wo.  73.    SECTION  THROUGH  A  SELF-CENTERING  FIXTURE  FOR  A 

RING  POT 


way  that  it  automatically  centers  the  work  from  the 
inside.  The  spring  at  the  base  of  the  plug  permits 
the  clamps,  F,  to  be  tightened  down  upon  the  face 
of  the  flange,  so  as  to  grip  the  work  securely.  While 
the  spring  plunger  centers  the  work,  it  does  not  in 
any  way  prevent  the  tightening  of  the  clamps,  and 
also  it  is  bored  out  and  ground  to  the  size  of  the 
pilot,  G,  of  the  boring  bar  in  which  the  cutter,  D,  is 
located.  The  principle  used  in  this  fixture  can  be 
applied  to  a  variety  of  work  on  turret  lathes  and 
boring  mills. 

Fixture  for  Thin  Aluminum  Castings.— The  in- 
stances which  have  been  previously  noted  have  all 
been  pieces  of  cylindrical  section,  but  it  frequently 


170 


TOOLS  AND  PATTERNS 


no.  74.    FACE-PLATE  FIXTURE  FOR  A  THIN  ALUMINUM  CASTING 


happens  that  the  work  which  is  to  be  machined  is  of 
irregular  form  requiring  special  arrangements  for 
locating  and  holding  it  One  point  in  the  design  of 
faee-plate  fixtures  for  such  work,  is  that  the  piece 
shall  be  held  in  such  a  way  that  it  will  be  firmly 
secured  and  will  not  be  distorted  in  any  way  by  im- 
perfect clamping.  An  example  is  shown  in  Figure  74, 
where  the  work  is  an  aluminum  casting,  A,  of  more 
or  less  rectangular  shape. 

The  V-prineiple,  so-called,  in  locating  work  on  fix- 
tures of  Tarions  kinds,  is  based  on  the  fact  that  a 
piece  of  work  can  be  put  into  a  V-shaped  block  or 
its  equivalent  in  such  a  way  as  to  act  as  a  locater 
whether  the  piece  is  a  rough  casting  or  one  that  has 
previously  been  machined.  It  might  almost  be  said 
that  the  basic  principle  of  jig  and  fixture  design  is  that 
Qf  locating  by  means  of  a  form  that  resembles  tlie 


FAOl-PIiATl  FIXTUBIS 


capital  letter  V — ^generally  written,  vee.  This  vee 
form  is  often  obtained  by  means  of  a  series  of  pins 
arranged  in  proper  formation  to  receive  the  work. 

In  the  instance  noted  in  Figure  74,  the  work.  A, 
is  placed  on  the  fixture^  B,  in  such  a  way  that  it 
locates  against  the  fixed  steel  pins,  C,  on  one  side 
of  the  fixture  and  the  pin,  D,  on  the  other  which 
form  a  sort  of  vee.  The  work  is  forced  over  against 
the  pin,  D,  in  one  direction  by  means  of  the  screw,  E; 
while  the  location  in  the  other  direction  is  performed 
by  means  of  the  swinging  clamp,  F,  operated  by  the 
hollow  set-screws,  G.  It  will  be  seen  that  the  swing- 
ing clamps,  F,  have  a  knife  edge  and  that  the  locat- 
ing pins  at  C  and  D  are  similarly  arranged.  The 
purpose  of  this  arrangement  is  to  sink  these  clamps 
and  pins  into  the  surface  of  the  casting  slightly,  so 
as  to  keep  it  from  being  pulled  out  while  the  piece 
is  being  machined.  As  the  bottom  of  the  casting  is 
also  rough,  it  must  also  be  supported,  so  that  the 
work  will  not  be  pushed  inward  toward  the  face  of 
the  fixture  by  the  pressure  of  the  cut.  This  is  taken 
care  of  by  means  of  the  spring  pins,  H,  which  adapt 
themselves  to  the  rough  surface  of  the  casting  and 
are  firmly  locked  in  position  by  the  set-screws,  K, 
in  the  outer  rim  of  the  face-plate.  In  addition  to  the 
spring  pins,  H,  the  work  is  given  a  positive  location 
on  the  fixed  pins,  N,  at  three  comers  of  the  piece. 

The  work  which  was  done  upon  this  casting  after 
it  was  located  and  clamped,  was  the  facing  of  the 
surface,  L,  the  turning  and  sizing  of  the  interrupted 
circular  tongue,  M,  and  the  boring  and  reaming  of 
the  center  hole  with  the  reamer,  0.  The  machine  on 


172 


TOOLS  AND  PATTBMNS 


Wa.  75.    PL.AN  AND  SECTION  OF  A  FIXTURE  WITH  SAFEGUARDING 

DEVICES 


which  •this  work  was  done  was  a  horizontal  turret 
lathe,  and  the  equipment  for  producing  the  work  was 
of  a  special  nature.  The  principles  shown  in  this 
fixture  may  he  applied  to  other  examples  of 

turret  lathe  work. 

Fixture  for  an  Irregular  Bracket. — The  protection 
of  workmen  engaged  in  manufacturing  is  often 
neglected  in  the  design  of  fixtures  for  turret  lathe 
work  and  other  work  that  requires  similar  handling. 
It  should  be  the  purpose  of  every  designer  to  make 
any  fixture  upon  which  he  is  engaged  so  that  it  will 
be  impossible  for  a  workman  to  become  injured  by  it. 
It  happens  occasionally  that  a  piece  of  work  w'th 
projecting  arms  or  lugs  is  to  be  held  on  a  face-pi  ate 
fixture,  and  when  such  cases  of  this  kind  arise  the 
designer  should  exercise  the  greatest  care  to  make 
the  fixture  in  such  a  way  that  the  workman  will  be 
protected  from  these  projections  as  they  revolve. 

An  example  of  this  kind  is  shown  in  the  piece  of 


FACE-PI4ATE  FIXTURES 


173 


work,  A,  in  Figure  75.  This  piece  has  been  previously 
machined  by  milling  the  surface,  B,  and  cutting  the 
tongue,  C.  It  will  be  seen  that  the  bracket  has  three 
projecting  arms,  D,  which,  if  unprotected,  might 
strike  a  workman  when  machining  the  piece.  The  fix- 
ture, therefore,  is  made  up  with  a  protecting  rim,  B, 
of  such  height  that  the  arms  do  not  extend  beyond 
it.  The  extra  cost  of  making  a  fixture  like  this  is 
very  slight,  and  in  addition  to  the  safety  feature, 
the  rim,  E,  also  acts  as  a  counterpoise  and  makes 
the  fixture  run  more  smoothly. 

The  work  is  located  on  the  fixture  against  the  fin- 
ished pads,  D,  and  the  tongue,  C,  lies  in  a  groove 
provided  for  it.  The  work  is  clamped  by  means  of 
the  four  straps,  F,  which  are  slotted  so  that  they  can 
be  moved  back  to  allow  the  work  to  be  set  up  and 
removed.  As  in  the  preceding  instance,  the  body  of 
the  fixture,  G,  is  screwed  to  the  nose  of  the  spindle, 
as  indicated.  The  work  to  be  done  in  this  case  is 
the  boring  of  the  hole,  H.  This  work  is  performed 
by  means  of  the  tool,  K,  mounted  on  a  bar  whose 
forward  end  is  piloted  by  a  bushing,  L,  in  the  face- 
plate fixture.  This  method  of  piloting  a  boring  tool 
or  other  cutting  tool  assists  greatly  in  producing  ac- 
curate work,  as  the  bushing  acts  as  a  guide  for  the 
bar  and  keeps  it  always  in  a  certain  relation  to  the 
work. 

Counterbalaaoed  Fixture  for  a  Conneetiiig  Bod.— 

For  a  piece  of  work  that  is  very  much  off  center 
and  is  to  be  bored  or  otherwise  machined  at  high 
speed,  it  is  often  necessary  to  provide  a  counter- 
balance on  the  fixture  in  order  to  prevent  excessive 


174 


TOOLS  AND  PATTSBNS 


WKL  7i.    CXnTHfEBBALAKCED  FAGE-FL4TB  fIXTUBE  VOS  A 

CONKEGTINQ  BOD 


vibration  from  the  unevenly  balanced  rotation  of  the 
work  and  fixture.  An  example  is  shown  in  Figure 
76.  The  fixture  here  is  designed  for  boring  and  ream- 
ing the  hole,  A,  in  the  connecting  rod,  B.  The  con- 
necting rod  has  been  previously  drilled  and  reamed 
at  the  small  end,  C,  and  it  is  necessary  to  locate  it 
for  the  remaining  operation  in  such  a  way  that  the 
hole,  A,  will  be  in  a  fixed  relation  to  the  previously 
reamed  hole,  C.  The  face-plate  fixture,  therefore,  is 
'  made  np  with  a  stnd  on  which  the  portion,  C,  locates. 
This  portion  of  the  work  is  drawn  back  against  the 
face  of  the  fixture  by  means  of  a  nut.  The  large  end 
is  then  correctly  located  by  means  of  a  V-block,  D, 
which  eratm  the  boss  at  C.  This  V-block  is  under 
ent,  as  indicated  in  the  sectional  view,  so  that  it 
tends  to  draw  the  work  back  against  the  face  of  the 
plate,  when  it  is  then  set  up  by  means  of  the  screw, 
K  This  screw  is  monnted  in  a  swinging  latch  and 


PACB-PLATB  FIXTURES 


175 


can  be  thrown  back  to  allow  the  workman  to  hook 
his  finger  into  the  recess,  F,  and  pull  the  block  away 
from  the  work. 

As  the  fixture  is  considerably  heavier  on  one  side 
than  on  the  other,  provision  is  made  for  counter- 
balancing it  by  means  of  the  Ings,  G.  These  Ings  are 
a  part  of  the  cast-iron  face-plate  and  are  made  heavy 
enough  and  thick  enough  to  more  than  balance  the 
mechanism  on  the  opposite  side  of  the  fixture.  • 

In  balancing  a  fixture  of  this  kind,  the  work  is 
placed  in  position  and  all  clamps  are  set  up  as  if  the 
machining  was  about  to  be  done.  The  fixture  is 
then  placed  on  an  arbor  and  allowed  to  swing  as  it 
will.  Naturally,  the  heaviest  portion  will  hang  down- 
ward. The  workman  then  drills  out  a  portion  of 
the  stock  from  the  lug,  as  indicated  by  the  holes,  K, 
and  tests  the  fixture  again,  continuing  the  operation 
until  a  proper  balance  is  obtained.  Sometimes  so 
much  stock  has  been  added  as  a  counterbalance  that 
it  becomes  necessary  to  mill  off  a  portion  of  the 
eounterpoise  in  order  to  bring  the  fixture  into 
balance. 

Fixture  with  Adjustable  Counterbalance. — A  fix- 
ture for  turret  lathe  work  or  for  the  engine  lathe 
may  be  needed  which  will  enable  several  pieces  of 
similar  character  to  be  machined  upon  it  by  making 
slight  modifications.  An  irregularly-shaped  piece  of 
work  which  has  a  counterbalanced  portion,  will  per- 
mit the  counterbalance  to  be  shifted  radially  on  the 
plate  so  that  it  will  balance  whatever  piece  is  being 
held  upon  it.  An  example  of  this  fixture  is  shown  in 
Figure  77. 


If  §  TOOLS  AND  PATTERNS 


mi.  Ti.  SEcnoK  and  plan  of  a  fixture  with  adjustable 

COUNTERBALANCE 


The  work  in  this  case  is  a  worm-gear  sector,  A, 
which  has  been  previously  bored  and  reamed  at  B, 
and  now  is  to  be  machined  as  indicated  at  C.  The 
work  18  located  m  a  fixed  stud  at  the  center  of  the 
fixtnre,  and  is  clamped  back  against  the  finished 
pad  by  means  of  the  nut,  E.  A  **C-washer,"  F,  is 
used  with  the  nut  so  as  to  permit  the  work  to  be 
ranoYed  rapidly.  By  using  such  a  device  it  will  be 
seen  that  the  nut  can  be  slightly  loosened,  the  C- 
washer  slipped  out  through  the  slot,  and  the  work 
immediately  released  without  removing  the  nut,  E. 

In  order  to  provide  the  portion  of  the  work,  C, 
with  a  rigid  support,  it  is  swung  around  against  the 
stop  pin,  H,  and  is  clamped  by  the  screw,  K.  As 
this  ride  of  the  fixture,  then,  is  so  much  heavier 
than  the  other,  it  is  necessary  to  provide  a  counter 
balance  at  L.  This  counterbalance  is  in  the  form  of 
a  segmental  block  with  two  bolts  through  it,  as  indi- 
cated at  M,  which  pass  through  the  two  slots,  and 


FACE-PLATE  FIXTURES 


177 


ullow  the  counterbalance  to  be  radially  adjusted  to 
compensate  for  pieces  of  different  size.  An  applica- 
tion of  this  principle  of  a  movable  counterbalance 
can  be  made  to  many  types  of  lathes,  turret  lathes, 
and  other  machines  of  similar  character.  In  cases 
where  the  work  to  be  machined  is  of  comparatively 
large  diameter,  so  that  the  work  runs  at  slow  speed, 
it  is  not  usually  necessary  to  counterbalance  it. 

Eccentric  Fixture  for  a  Ring  Pot.— In  making  up 
packing  rings  for  automobile  motors,  compressors, 
and  the  like,  an  eccentric  ring  is  frequently  desir- 
able. The  ordinary  process  of  machining  one  of 
these  is  by  means  of  an  eccentric  turning  device 
which  will  be  described  in  Chapter  XIV.  As  an 
eccentric  device  of  the  character  mentioned  is  some- 
what expensive,  however,  the  small  manufacturer 
frequently  dispenses  with  such  a  device  and  handles 
the  work  in  a  slightly  different  manner.  But  when 
the  device  is  employed,  the  work  is  turned  eccen- 
trically by  means  of  the  device  and  is  also  bored 
concentrically  at  the  same  time,  thus  saving  a  con- 
siderable amount  of  time  in  the  process. 

When  an  attachment  of  the  kind  mentioned  is  not 
Bsed,  it  is  customary  to  bore  the  work  in  one  opera- 
tion. The  outside  eccentric  is  then  turned  in  an- 
other operation,  either  by  means  of  an  eccentric  arbor 
or  by  placing  the  pot  from  which  the  rings  are  to 
be  made  on  a  fixture  which  can  be  set  eccentrically 
after  the  hole  has  been  bored. 

In  Figure  78,  the  ring  pot.  A,  is  located  on  the  face 
of  the  fixture  by  means  of  the  lugs  and  clamps  shown 
at  B.   The  face-plate  consists  of  two  parts,  one  of 


178 


TOOLS  AND  PATTERNS 


110.78.    TOCENTiaC  FmiTRB  ItIR  A  RINO  POT 


which,  C,  is  screwed  to  the  end  of  the  spindle,  and 
the  other,  D,  is  fastened  to  it  by  means  of  the  bolts, 
B,  which  enter  slotted  holes  in  the  plate,  D,  to  allow 
for  a  slight  movement  of  the  upper  plate  on  the 
lower.  The  plate,  C,  is  grooved  at  F,  directly  across 
its  face;  and  the  plate,  D,  is  provided  with  a  tongue 
to  slide  in  this  groove. 

In  operation,  the  hole,  G,  is  first  bored  by  a  boring 
bar  piloted  in  the  bushing,  H,  in  the  movable  plate. 
After  this  operation  has  been  done,  the  nnts  at  £  are 
loosened  and  the  plate  is  set  over  the  amount  indi- 
cated by  the  line  at  K.  The  correct  distance  is  de- 
termined by  pins  and  bushings  at  L  and  M. 

This  type  of  eccentric  fixture  is  very  simple  and 
answers  all  purposes  for  work  of  this  character.  It 
is  unnecessary  to  counterbalance  the  fixture  unless 
the  eccentricity  is  so  great  that  the  fixture  runs  out 
of  balance  when  it  is  set  over. 

Swinging  Eocmtric  Fizlnre.— A  fixture  may  be 
required  that  will  permit  a  slight  amount  of  adjust- 
ment so  that  it  can  be  set  to  give  two  or  three  eccen- 


FACE-PLATE  FIXTUEEg 


179 


FOR  A  PACKINO  MNQ  POT 


tricities.  In  order  to  provide  for  a  contingency  such 
as  this  it  is  necessary  to  make  the  fixture  so  that 
the  stops  which  limit  the  throw  of  the  eccentric  are 
adjustable.  An  example  of  such  a  fixture  is  shown 
at  A,  Figure  79.  The  fixture  is  designed  for  a  hori- 
zontal turret  lathe  for  boring  and  turning  eccen- 
trically the  worki  B.  The  ring  pot,  B,  which  is 
to  be  turned  and  bored,  is  held  on  the  plate,  C, 
in  practically  the  same  way  as  the  pot  shown  in  the 
previous  illustration.  The  mounting  of  the  plate  on 
the  body  of  the  fixture,  however,  is  arranged  in  a 
different  way.  In  this  case,  the  plate  is  pivoted  so 
as  to  swing  from  the  stud,  D.  The  lower  portion 
of  the  body  plate.  A,  is  provided  with  a  stop  ex- 
tending out  through  a  slot  in  the  plate,  as  indicated 
at  E.  Adjusting  screws,  F,  on  the  surface  of  the 
fixture  at  E,  provide  for  lateral  movement  of  the 
plate,  and  suitable  clamping  bolts,  G,  on  each  side 
of  the  fixture  hold  it  in  place. 

When  it  is  desired  to  set  over  the  work  to  produce 
the  eccentric,  the  bolts,  G,  are  loosened  and  the  plate 


180 


TOOLS  AND  PATTERNS 


swung  over  until  the  stud,  E,  strikes  against  the  set- 
screws,  F,  The  amount  which  these  set-screws  per- 
mit the  plate  to  move,  govern  the  amount  of  eccen- 
tricity. The  spacing  of  the  stop,  E,  is  twice  the 
distance  from  the  pivot  point,  D,  to  the  center  of 
the  work,  so  that  the  apmuBt  of  movement  at  F  is 
exactly  twice  the  eccentricity  produced.  Fixtures  of 
this  kind  can  be  used  with  success  on  a  great  variety 
of  work,  and  as  they  are  cheaply  made  and  very 
serviceable  they  may  be  considered  as  excellent  types 
of  eccentric  turning  and  boring  equipment 


CHAPTER  XIII 


ABBOBS  AND  MANDRELS 

Definition  of  Terms. — The  term  arbor  is  applied  to 
the  cylindrical  piece  used  for  mounting  cutters  upon 
a  milling  machine.  It  is  also  applied  to  the  device 
used  to  center  a  piece  of  work  by  a  previously  bored 
or  reamed  hole  so  as  to  bear  a  distinct  relation  to 
the  hole.  The  term  mandrel  is  almost  sjmonynious 
with  the  term  arbor  as  applied  to  holding  work. 
For  example,  the  expressions,  **an  arbor  for  a  %-inch 
hole,"  or  **a  mandrel  for  a  %-inch  hole,"  are  used 
interchangeably.  The  term  mandrel,  however,  is  not 
used  synonymously  with  the  term  arbor  when  applied 
to  the  device  for  holding  cutters  in  a  milling  ma- 
chine. These  would  always  be  referred  to  as  cut- 
ter arbors.'* 

AYbors  are  of  several  kinds — ^plain  arbors,  threaded 
arbors,  expanding  arbors,  and  cutter  arbors.  The 
last  mentioned  is  generally  used  in  the  milling  ma- 
chine for  holding  om  or  more  cutters  in  position. 
This  type  of  arbor  is  quite  simple  and  is  variously 
made  as  a  part  of  the  standard  equipment  for  a  mill- 
ing machine.  Such  an  arbor  is  shown  in  Figure  80 
at  A.  The  tang  end,  B,  is  tapered  to  fit  the  milling 
machine  spindle,  and  may  be  used  in  an  adapter 
when  the  spindle  taper  and  that  of  the  arbor  do  not 

ISl 


m 


TOOLS  AND  PATTERNS 


1— e-M 


MG.  80.    ABBOB  FOE  MILUNG  MACHINE,  ABOVE,  AND  VOR  PliAIN 

LATHE,  BELOW 


 m-1 

■ 

na.  SL    EXPANDING  SHOB  T¥FB  €P  AIDOfI 
W.  H.  Nldwlflon  ft  Oa 


ARBORS  AND  MANDRELS  183 

correspond.  The  cutters,  C,  are  placed  on  the  arbor 
with  one  or  more  spacing  collars,  D,  between  them 
to  space  the  distance,  B,  correctly  for  the  work  re- 
quired. There  is  little  to  be  said  about  milling  ma- 
chine arbors  as  their  design  is  so  extremely  simple. 

A  plain  arbor  or  mandrel,  indicated  at  F,  Figure 
80,  is  usually  found  in  the  tool  crib  in  all  standard 
sizes.  It  is  made  up  for  standard  sizes  of  holes, 
usually  with  a  taper  of  about  0.006  inch  per  inch  of 
length.  When  a  piece  of  work,  such  as  that  shown 
at  G,  is  to  be  turned  on  its  surface  by  the  tool,  H, 
after  it  has  been  reamed  in  a  previous  operation, 
it  is  placed  under  an  arbor  press  and  the  arbor,  F, 
is  forced  into  it  under  pressure.  As  the  arbor  is 
tapered,  it  will  wedge  firmly  into  the  work  so  that 
there  will  be  no  slipping  when  the  pressure  of  the 
cut  is  applied.  Arbors  of  this  kind  are  usually  de- 
signed to  be  dogged  to  the  face-plate,  as  indicated  in 
the  drawing. 

Arbor  with  Expanding  Shoes.— It  is  often  neces- 
sary to  hold  a  piece  of  work  that  is  slightly  over  or 
under  a  standard  size  on  an  arbor,  to  perform  some 
operation  upon  the  piece  which  will  be  absolutely 
concentric  with  a  previously  finished  hole.  Two 
methods  of  holding  are  possible.  The  toolmaker  or 
machinist  can  make  up,  in  comparatively  short  time, 
such  an  arbor  as  that  shown  in  i'igure  80,  of  such 
a  size  as  to  suit  the  hole  in  the  work.  Or,  if  the  tool 
crib  is  well  equipped  with  expanding  arbors,  it  may 
not  be  necessary  to  piake  up  a  special  one  for  the 
job. 

Expanding  arbors  are  of  several  types,  but  perhaps 


m 


TOOLS  AND  PATTEBNS 


the  most  useful  type  is  that  shown  in  Figure  81. 
Such  an  arbor  can  be  purchased  in  Yarious  sizes  to 
suit  any  given  eonditions.  The  body  of  the  arbor 
is  hardened  and  ground  to  cylindrical  form.  It  is 
furnished  with  four  slots,  A,  into  which  are  fitted 
the  shoes,  3.  It  will  be  noticed  that  the  slots  are 
cut  on  a  slight  longitudinal  taper,  so  that  when  a 
piece  of  work  is  placed  on  the  shoes,  they  may  be 
adjusted  along  the  tapered  slots  to  the  required 
diameter.  The  retaining  ring,  C,  at  each  end  of  the 
shoes  are  slotted  to  receive  the  shoes  and  hold  them 
on  the  arbor  when  not  in  use.  This  type  of  expand- 
ing arbor  should  form  a  part  of  the  tool  crib  equips 
ment  and  should  be  bought  in  a  sufficient  range  of 
sizes  to  cover  the  requirements  of  the  class  of  work 
which  is  being  done.  This  same  type  is  also  largely 
used  in  general  manufacturing,  and  its  adaptability 
suits  it  for  an.  infinite  number  of  pieces. 

Sidit  ting  Ezpandiiig  Arbor.— It  is  sometimes  nec- 
essary to  refinish  the  outside  of  a  piece  of  work  and 
make  sure  that  it  is  absolutely  concentric  with  the 
center  of  the  hole  that  has  been  previously  machined. 
A  common  type  of  arbor  for  this  purpose  is  shown 
in  Figure  82  at  A.  Let  it  be  supposed  that  the  work, 
B,  is  to  be  held  by  the  hole  previously  finished  in  it, 
and  that  the  work  is  to  done  on  an  engine  lathe.  A 
steel  arbor,  C,  is  then  made  up  with  a  slight  taper 
along  its  length.  A  sleeve,  D,  is  split  along  its  length 
at  E,  and  is  tapered  on  the  inside  so  as  to  fit  the 
taper  on  the  arbor,  C.  When  the  work,  B,  is  placed 
in  position  and  forced  onto  the  arbor  over  the  split 
ring,  the  ring  expands  slightly  as  it  is  forced  up  on 


AKBOBS  AND  MANDRELS  185 

■ 


no.  82.    SPUT-RING  EXPANDING  ABBORS 

the  taper  until  it  grips  the  work  securely,  thus  hold- 
ing it  so  that  it  can  be  machined  readily.  '  This  type 
of  arbor  is  not  exceptionally  good,  as  it  is  simply 
split  longitudinally.  When  it  opens  up,  the  ring,  D, 
therefore,  is  slightly  elliptical  and  does  not  expand 
evenly  all  over.  As  a  cheap  arbor  that  can  be  used 
for  a  few  pieces,  such  a  device  will  answer  the  pur- 
pose in  many  instances,  but  it  should  not  be  used 
for  work  requiring  great  accuracy. 

A  much  better  type  of  arbor,  shown  at  F,  can  be 
used  for  work  requiring  great  accuracy.  Roughly, 
the  principle  of  the  two  arbors  is  the  same,  except 
that  in  the  instance  previously  mentioned  the  ring 

split  in  one  direction  only,  while  in  the  example, 
^,  the  ring,  G,  is  split  longitudinally  into  three  slots, 
running  from  one  almost  to  the  other  and  spaced  120 
degrees  apart,  as  indicated  at  H.    There  are  also 


186 


TOOLS  AND  PATTERNS 


three  other  slots  starting  from  the  other  end  of  the 
ring,  spaced  equidistantly  between  the  slots  men- 
tioned, and  also  running  nearly  to  the  end  of  the 
ring.  It  will  be  seen  that  this  arrangement  allows 
the  ring  to  be  expanded  equally  all  over,  making 
a  mueh  better  eonstmetion  than  that  previously 
described. 

An  additional  requirement  on  this  arbor  is  seen 
in  the  nut,  K,  and  washer,  L,  by  means  of  which 
the  ring  is  forced  back  on  the  taper,  M,  so  that  it 
expands  and  holds  the  work.  In  the  example  shown 
at  A,  it  is  necessary  to  use  an  arbor  press  to  force 
the  work  on,  or  else  to  drive  it  on  with  a  piece  of 
babbitt  or  wood.  For  finishing  the  outside  of  collars, 
small  blanks,  and  other  work  of  similar  character,  the 
type  of  arbor  shown  at  F  is  very  useful,  and  is  fre- 
quently found  among  the  tools  used  for  general 
manufacturing. 

Expanding  Arbor  for  an  Automobile  Flange.— 
Special  arbors  may  be  made  up  to  suit  a  particular 
case  when  a  number  of  pieces  are  to  be  manufac- 
tured. One  such  is  shawn  in  Kgure  83.  In  this 
case  the  work,  A,  is  an  automobile  flange  which  has 
been  previously  bored  and  reamed  at  B  and  C.  As 
it  is  necessary  to  finish  the  end,  D,  and  the  flange, 

E,  the  method  of  holding  by  the  inside  surface  was 
devised. 

The  machine  to  which  this  arbor  was  applied  is 
a  horizontal  turret  lathe.  The  method  of  holding 
was  by  means  of  the  collet  mechanism  with  which 
the  turret  lathe  is  furnished,  the  stem  of  the  arbor, 

F,  being  held  as  indicated  in  exactly  the  same 


ABBOBS  AND 


MAllHI^' 


187 


ilO.  83.    SECTION  TmiOUGH  EXPANDINa  AJSBOB  FOB  MM 

AUTOMOBUfE  FLANGE 

manner  as  that  used  to  hold  a  piece  of  bar  stock. 
The  work  then  was  placed  on  the  portion,  G,  which 
made  a  nice  fit  at  this  point.  After  the  work  was 
so  placed,  the  tupered  screw,  H,  was  set  up,  thus 
expanding  or  opening  up  the  arbor  to  grip  the  points, 
C.  A  shoulder  was  also  provided  on  the  arbor  to 
give  longitudinal  location  at  K. 

When  making  use  of  the  collet  mechanism  to  hold 
an  arbor  for  manufacturing  purposes,  it  is  necessary 
to  make  sure  that  the  collet  is  perfectly  true;  other- 
wise  the  arbor  might  run  out  of  truth  and  work 
naight  be  produced  which  would  not  be  concentric. 

An  arbor  of  this  kind  must  be  made  of  tool  steel, 
tempered  slightly  in  order  that  it  may  expand  prop- 
erly and  come  back  to  place  again  when  the  tapered 
screw  is  released.    It  will  be  understood  that  the 


i 


188 


TOOLS  AND  PATTKRNS 


portion  of  the  arbor  whieh  is  controlled  by  the  ex- 
pansion of  the  tapered  screw,  is  slotted  into  three 
sections,  so  that  it  can  be  opened  up  slightly  by 
the  action  of  the  screw  mentioned. 

KYpandlng  Axboir  for  an  Adjuiting  Nut— Occa- 
sionally several  pieces  of  similar  character  but 
slightly  different  in  size  may  be  machined  by  the 
same  or  similar  equipment  on  a  turret  lathe.  An 
example  is  shown  in  the  pieces  A  and  Figure  84. 
These  pieces  are  bronze  adjusting  nuts  in  two  sizes, 
slightly  different  both  in  outside  diameter  and  in  the 
location  of  the  spanner  holes  shown  at  C. 

Several  thousands  of  these  parts  were  to  be  made, 
and  as  it  was  desirable  to  make  up  the  equipment 
as  cheaply  as  possible,  the  arbor  was  so  designed 
that  it  could  be  used  for  both  pieces  by  the  aid  of 
an  adapter.  *A  special  nose  piece,  was  screwed 
to  the  end  of  the  spindle,  as  indicated,  shouldered  at 
E  to  receive  the  ring,  F,  which  was  used  for  the 
piece,  A,  and  also  could  be  fitted  with  the  ring,  6, 
for  use  with  the  piece,  B.  In  each  case  the  rings 
were  provided  with  pins,  H  and  K.  These  pins 
entered  the  spanner  holes,  as  indicated,  and  assisted 
in  driving  the  work-an  essential  point  in  connection 
with  an  arbor  on  whieh  any  heavy  work  is  to  be 
done.  The  outside  of  the  nut  in  each  case  was  to 
be  threaded  with  an  opening  die,  so  that  the  pulling 
action  of  the  cut  was  rather  severe. 

A  split  ring,  similar  to  the  one  shown  at  G,  Figure 
82,  was  used  to  center  the  work.  This  ring,  of  course, 
was  very  much  smaller  than  the  one  previously  nien- 
tionedy  but  the  method  of  splitting  was  the  same. 


ABBORS  AND  MANDRELS  189 


p 


WO.  84.    IZPAKniNO  ARBOB  FOB  AN  ADJtJSTINQ  NUT 

In  this  arbor,  it  will  be  observed,  expansion  was 
procured  by  means  of  the  tapered  plug,  L,  which 
had  a  generous  bearing,  M,  in  the  nose  piece.  The 
threaded  portion,  N,  was  somewhat  loose  in  order 
that  the  centering  action  might  not  be  governed  by 
the  threaded  portion,  but  might  be  absolutely  de- 
termined by  the  cylindrical  part,  M.  The  thread  was 
sunply  used  as  a  means  of  drawing  in  on  the  plug 
and  thus  expanding  the  ring  at  L. 

Applications  of  this  principle  may  be  made  to 
many  kinds  of  narrow  work  when  it  is  necessary  to 
do  heavy  cutting  on  the  outside.  It  occasionally 
happens  that  one  or  more  holes  are  drilled  in  a  piece 
of  work  in  order  to  provide  a  means  of  driving.  In 
the  particular  case  mentioned,  the  spanner  holes, 
fortunately,  made  this  unnecessary. 

Expaadingr  Arbor  for  a  Bevel  Pinion.— It  is  par- 
ticularly necessary  to  machine  a  bevel  pinion  in  such 


190 


TOOLS  AND  PATTERNS 


IW.  85.    8SCni»f  THROUGH  BXPANDINO  SHOE  ARBOR  FOR  A 


BBVEKf  FUnON 

a  way  that  the  outside  of  the  gear  is  in  perfect  con- 
centricity with  the  hole.  In  order,  therefore,  to  pro- 
vide a  means  by  which  snch  an  effect  may  be  secured, 
it  is  necessary  at  times  to  design  an  arbor  of  small 
dimensions  with  adjustable  features  to  provide  for 
self-centering. 

Occasionally,  also,  the  kind  of  tooling  which  is  to 
be  used  on  a  piece  of  this  kind  has  a  certain  effect 
on  the  design  of  the  arbor.  Such  an  instance  is 
shown  in  Figure  85.  This  is  an  unnsual  type  of 
arbor  for  it  is  somewhat  delicate  in  construction. 
Its  mechanical  features,  however,  are  of  considerable 
value,  and  the  principle  shown  may  be  applied  to 
other  work  of  similar  character. 

This  arbor  was  made  np  for  use  on  a  horizontal 
turret  lathe  in  connection  with  a  special  taper  at- 
tachment for  generating  the  angular  surface  of  the 
pinion,  A,  which  had  previously  been  bored  and 
reamed  on  another  machine.  At  the  same  setting 
of  the  work,  the  face,  B,  was  to  be  machined.  Pre- 


ARBORS  AND  MANDRELS 


191 


vious  to  the  operation  shown  and  after  the  hole  had 
been  reamed,  a  keyway,  C,  was  cut  in  the  pinion  in 
order  to  provide  an  efficient  means  of  driving  while 
the  heavy  cutting  was  taking  place  at  A.  The 
spindle  of  the  machine  was  provided  with  an  adapter, 
D,  which  had  a  tapered  hole,  E,  where  the  stem,  F, 
of  the  arbor  was  located.  A  key  driver,  G,  was  also 
added  to  make  the  driving  positively  certain. 

As  will  be  seen  from  the  illustration  the  work 
located  on  the  cylindrical  surface,  H,  which  was 
made  0.002  of  an  inch  under  the  size  of  the  hole  in 
the  pinion.  There  are  three  slots  cut  in  the  arbor  to 
receive  the  shoes,  K,  which  were  beveled  slightly  on 
their  internal  faces  so  as  to  fit  the  taper  on  the  oper- 
ating rod,  L.  This  operating  rod  was  pushed  back 
mto  the  arbor  by  means  of  the  screw,  M.  The  por- 
tion, N,  is  ground  to  fit  a  shell  mill  held  in  the  tur- 
ret and  used  for  facing  the  angular  surface,  B.  As 
the  operating  rod  was  pushed  inward  by  means  of 
the  screw,  M,  the  three  shoes,  K,  were  forced  out- 
ward against  the  inside  of  the  hole  in  the  pinion, 
thus  providing  an  efficient  centering  action.  A  sec- 
tional view,  taken  directly  across  the  arbor  and 

is  shown  at  0,  and  a  correspond- 
ing section  of  the  operating  rod  is  indicated  at  P. 

Although  an  arbor  of  this  kind  is  fairly  exgMlMve 
and  rather  delicate  in  its  construction,  it  may  be 
used  in  a  number  of  cases  where  the  greatest  accu- 
i*acy  is  necessary.  The  equipment  mentioned  is 
really  the  '^ast  word"  in  the  design  of  an  accurate 
expanding  arbor.  An  additional  refinement  is  found 
^  the  knurled  nut,  Q,  which  is  used  to  start  the 


TOOLS  AND  pj^ffEf^ 


work  after  it  has  been  inachined  in  the  event  that 
it  might  stick  slightly. 

Expanding  Pin  Chuck  for  a  Kston.— Automobile 
pistons,  A,  Figure  86,  and  certain  other  classes  of 
work,  are  made  in  such  form  that  the  inside  portion 
is  "cored.'*  A  core,  if  of  large  size,  but  not  extend- 
ing  completely  through  the  work,  always  shows 
a  tendency  to  sag  more  or  less  while  the  casting  is 
made,  so  that  the  resulting  work  is  not  absolutely 
concentric.  This  is  particularly  true  of  automobile 
pistons.  Therefore,  such  work  must  be  held  in  such 
a  way  that  wh^  it  is  machined  on  the  outside,  the 
surface  will  be  very  nearly  concentric  with  the  in- 
side rough-cored  surface,  no  matter  whether  the  cast- 
mg  is  true  when  in  the  rough  state  or  not. 

It  is  logical  to  hold  such  work  for  the  machining 
processes  from  the  inside  core,  so  as  to  be  sure  of  the 
concentricity.  This  method  of  holding  makes  neces- 
sary a  rather  elaborate  arbor.  Arbors  made  for  this 
purpose  are  of  various  forms,  each  having  some  par- 
ticular claim  for  its  existence.  The  example  shown 
in  Figure  86  is  one  of  the  best  for  this  class  of  work, 
and  has  been  built  to  suit  numerous  cases  with  the 
most  satisfactory  results.  It  is  by  no  means  a  cheap 
arbor,  and  it  requires  the  greatest  care  in  design 
and  the  most  careful  workmanship  in  machining.  Yet 
its  action  is  so  satisfactory  that  in  the  event  of  a 
large  number  of  pieces  to  be  machined,  the  first  cost 
of  the  arbor  may  almost  be  neglected. 

The  arbor,  shown  at  B,  is  screwed  to  the  end  of 
the  spindle,  as  indicated.  It  is  made  of  machine 
Steel,  carbonized,  hardened,  and  ground  in  its  essen- 


ARBOBS  AMD  MANPBKLS  Ida 


m,  86.    PLAN  AND  SECTION  OP  EXPANDING  PIN  CHUCK  FOR  A 

PISTON 


tial  parts.  Six  pins  are  so  spaced  as  to  be  equi- 
distant around  the  periphery,  at  C,  while  at  D  they 
are  arranged  in  such  a  way  as  not  to  interfere  with 
the  wrist  pin  bosses  shown  in  the  upper  sectional 
view  at  E.  The  lower  ends  of  the  pins  are  beveled 
to  ride  on  the  two  cams,  F  and  G.  These  cams  are 
threaded  right  and  left  hand  to  fit  the  screw,  H, 
which  is  provided  with  a  slot,  K,  for  operating  pur* 
poses — ^a  pair  of  bevel  pinions,  at  L  and  M,  being 
used  as  the  operating  means.  It  will  be  seen  that 
when  the  pinion,  L,  is  revolved  by  means  of  a  special 
socket  wrench,  the  motion  is  transferred  to  the 


IM  TOOLS  AND  PATTERNS 


pimon,  M,  which  turns  the  threaded  shaft,  H,  and 
causes  the  cams,  F  and  G,  to  approach  or  recede 
from  each  other  according  to  tie  direction  of  rota- 
tion. 

A  valuable  point  in  connection  with  this  piece 
of  mechanism  is  the  fact  that  the  pressure  exerted 
on  the  pins  C  and  D  is  eqnaHzed,  so  that  the  amount 
of  force  exerted  on  all  six  pins  is  the  same.  This 
equalizing  action  is  caused  by  the  *  Afloat"  in  the  two 
cams.  As  the  shaft,  H,  is  free  to  move  slightly 
longitudinally,  the  pressure  is  distributed  on  the 
two  cams  in  an  equal  ratio.  The  cams  are  prevented 
from  turning  by  means  of  the  set-screws,  0. 

Threaded  and  Knock-off  Arbors.— Tapping  out  a 
piece  of  work  in  such  a  way  that  the  threaded  por- 
tion will  be  in  perfect  concentricity  with  the  out- 
side and  with  the  ends  of  the  work,  is  a  difficult  oper- 
ation.  It  is,  therefore,  necessary  to  provide  some 
means  of  re-finishing  the  outside  of  the  work  or  the 
ends,  using  the  threaded  portion  as  a  locating  point. 
The  simplest  type  of  arbor  which  can  be  devised  for 
holding  a  piece  of  threaded  work  is  that  shown  at  A, 
Figure  87.  In  this  arbor  a  portion,  B,  is  threaded 
to  receive  the  work,  which  is  screwed  upon  it  and 
makes  up  against  the  shoulder,  D. 

This  arbor  is  held  on  centers  in  an  engine  lathe 
and  is  driven  by  means  of  a  dog  in  the  usual  man 
ner.  While  it  will  give  satisfactory  results,  it  is 
by  no  means  a  convenient  type  to  use,  for  the  reason 
that  the  pressure  of  the  cut  in  finishing  the  outside 
of  the  work  is  such  that  it  causes  the  piece  to 
**freeze''  up  against  the  shoulder,  D,  so  that  it  is 


AlBORS  Am  MANDRELS  195 


KEG.  87.    THRSADED  AND  KHOGK-OFF  ARBORS 

difficult  to  remove  it  without  the  use  of  a  pipe  wrench 
or  special  clamps. 

A  much  better  type  of  arbor  and  one  which  over- 
comes this  trouble,  is  shown  at  E  in  the  lower  illus- 
tration. This  arbor  is  threaded  in  the  same  manner 
as  the  upper  one  in  Figure  87,  except  that  the  work, 
F,  does  not  make  up  against  the  shoulder,  G,  but 
rather  against  the  flange,  H.  This  flange,  however, 
fits  against  a  shoulder,  K,  on  the  arbor,  so  that  the 
longitudinal  location  of  the  work  always  comes  the 
same. 

Provision  for  removing  the  work  without  difficulty 
is  as  follows:   The  arbor  is  threaded,  at  L,  with  a 


196 


TOOLS  AND  PATTERNS 


coarse  left-hand  thread  on  which  the  flange,  H,  is 
screwed  until  it  strikes  against  the  shoulder,  K.  The 
flange  is  provided  with  two  lugs,  M,  on  opposite  sides 
m  order  to  make  the  matter  of  releasing  easy.  When 
the  work  has  been  finished,  it  is  only  necessary  to 
strike  either  of  these  lugs  a  sharp  blow  with  a  bab- 
bitt hammer  or  piece  of  wood  and  the  work  is  at 
once  released,  because  the  end  of  the  work  is  backed 
away  from  the  flange,  H.  It  is  an  easy  matter,  then, 
to  release  the  jriece  from  the  arbor  without  the  aid 
of  any  tools  except  the  workman's  hands. 

Knock-oflf  Arbor  for  Threaded  Collars.— An  excel- 
lent  example  of  a  knock-off  arbor  designed  for 
handling  a  number  of  pieces  of  threaded  work  of 
different  sized  threads  and  pitches  is  shown  in  Figure 
88.    There  were  a  number  of  collars  such  as  those 
shown  at  A,  B,  and  C;  the  manufacturing  require- 
ments of  which  made  it  necessary  to  have  the  ends 
square  with  the  thread.  An  equipment  was  designed, 
therefore,  so  that  by  means  of  adapters,  such  as  those 
shown  at  D,  E,  and  F,  and  with  threaded  'arbors 
as  that  shown  tft  G,  a  number  of  different  sizes  could 
be  handled  with  little  trouble.    A  master  bushing, 
H,  was  inserted  in  the  spindle  of  a  turret  lathe,  as 
indicated.    In  it  the  adapters,  G,  were  located  by 
means  of  the  taper  at  K,  and  were  drawn  by  a  bolt, 
L,  provided  with  a  spherical  washer,  M,  in  order  to 
equalize  any  strain  caused  by  the  action  of  the  bolts 
m  drawing  the  work  back  into  the  taper,  K.  The 
master  bushing  was  provided  with  a  threaded  por- 
tion, N,  and  a  shoulder,  0,  against  which  a  plate,  P, 
gave  the  correct  location  to  the  work.  The  threaded 


ARBOES  AND  MANDRELS 


197 


m.  88.    KHOCK-OTF  ARBCm  im  *mEEAllED  OOU4ABS 

portion  was  made  left  hand,  as  in  the  preceding 
instance.  A  knock-off  flange,  Q,  was  made  with  a 
finished  pad,  E,  so  that  a  spacing  collar,  F,  could 
be  used  in  connection  with  the  work. 

In  operation,  the  threaded  flange  is  screwed  .up 
'Jntil  it  makes  against  the  shoulder  at  0;  the  spacer, 
P.  is  inserted,  and  the  work,  C,  is  screwed  onto  the 
arbor.  Then,  after  the  machining  has  been 
*e  lugs,  S,  are  given  a  sharp  blow  with  the  hammer 
or  a  block  of  wood,  and  the  work  is  immediately 


TOOIiS  AND  PATTEBMS 


released  so  that  it  can  be  removed  from  the  arbor. 
I  nlllll  up  an  equipment  of  this  kind  to  handle 
twelve  pieces  of  different  diameters  and  different 
threads,  and  its  operation  was  very  satisfactory. 
Moreover,  the  same  principle  may  be  applied  in  many 
other  cases  where  threaded  work  is  to  be  machined. 

Special  Arbor  for  an  Eccentric  Packing  Sing.— 
The  packing  ring,  shown  at  A,  Mgnre  89,  is  a  type 
commonly  nsed  for  compressors  and  automobile 
motors.  The  operations  on  a  ring  of  this  kind  are 
as  follows:  A  pot  casting  is  first  made  np  and  held 
in  snch  a  way  that  it  can  be  tnmed  eccentrically 
and  bored  at  the  same  time.  In  the  same  operation 
the  rings  are  cut  off  from  i/4-inch  to  %-inch  wide. 
After  they  have  been  cut  off  they  are  ground  to  the 
correct  thickness,  and  are  then  cut  with  a  diagonal 
cut,  as  indicated  at  B,  and  from  5/32  to  3/16  of  an 
inch  of  metal  is  taken  off  of  each. 

When  one  of  these  rings  is  closed  up  so  that  the 
edges  at  B  are  in  contact,  it  will  be  found  that  the 
ring  is  slightly  elliptical.  To  counteract  this  ellipse 
and  to  make  the  ring  true  once  more,  it  must  be 
turned  or  ground  on  the  outside.  A  special  arbor 
of  an  unusual  type  is  used  for  this  purpose,  the  con- 
struction being  practically  the  same  whether  it  is 
used  for  turning  or  grinding.  The  arbor,  C,  is  ar- 
ranged so  that  it  can  be  dogged  at  one  end  and  held 
on  centers  in  an  engine  lathe  or  on  a  cylindrical 
grinder.  A  locating  flange,  D,  and  a  sliding  sleeve, 
E.  fit  snugly  on  the  portion,  C. 

The  particular  type  of  arbor  shown  in  this  illus- 
tration is  intended  to  take  two  packing  rings,  F. 


AEBOBS  AND  MANDBELS  199 


Wm,  89.    SPECIAL  ABBOR  FOR  AN  ECCENTRIC  PACKING  KINO 


These  are  held  firmly  against  the  shoulder  by  means 
of  the  threaded  piece,  G,  which  is  hexagonal  so  that 
a  wrench  can  be  used  upon  it.  In  using  this  arbor, 
the  hexagonal  nut,  H,  is  removed  and  the  rings,  F, 
are  set  into  the  sleeve;  the  threaded  nut  is  then 
screwed  up  upon  them  until  they  are  firmly  held 
against  the  shoulders  at  D.  The  sliding  sleeve  is 
now  pulled  back  out  of  the  way,  until  the  detent 
pin,  K,  snaps  into  the  groove,  L,  which  keeps  it  out 
of  the  way  of  the  tool  while  the  work  is  being  done. 
An  air  hole  is  provided  at  M,  in  order  to  relieve  the 
suction  and  allow  the  sleeve  to  be  pushed*  back 
away  from  the  work  without  difficulty.  Were  it  not 
for  this  provision  it  would  be  practically  impossible 
to  pull  back  the  sleeve. 

Arbors  of  this  kind  are  in  very  common  use  in 
automobile  factories  throughout  the  country.  Prac- 
tically all  are  made  on  the  same  general  style,  al- 
though refinements  are  sometimes  found  tending 
toward  more  rapid  manipulation  and  quicker  hand- 
ling. However,  the  type  shown  is  an  excellent  ex- 
ample of  an  arbor  for  work  of  this  character. 


4 


CHAPTBB  XIV 
GENERATING  AND  FOEMING  ATTACHMENT 

Generating  Curved  Surfaoes.— A  cylindrical  piece 
of  work  may  be  formed  to  a  prescribed  shape  by 
means  of  a  tool  itself  shaped  to  the  correct  contour, 
or  the  shape  may  be  generated  by  a  single  tool  nsed 
with  a  special  attachment  on  an  engine  lathe,  a  turret 
tathe,  or  a  vertical  boring  mill.  If  the  work  to  be 
formed  is  not  cylindrical,  a  suitable  forming  attach- 
ment can  be  applied  either  to  a  planer,  a  shaper, 
or  a  millmg  machine  in  sueh  a  way  as  to  produce 
the  desired  shape,  either  with  a  cutter  of  special 
form  or  with  a  forming  plate  that  controls  the  move- 
ment of  the  cutting  tool. 

Attachmente  for  the  planer,  shaper,  and  milling 
machme  are  rarely  nsed,  except  on  special  work,  and  as 
they  are  highly  specialized  and  the  design  is  gen- 
erally developed  to  suit  the  particular  pieces  to  be 
machmed,  it  is  not  necessary  to  describe  them  here. 

For  some  very  large  work,  a  radial  attachment 
can  be  applied  to  a  planer  and  used  to  generate  a 
curved  surface.  It  is  also  possible  to  apply  a  taper 
attachment  to  a  planer,  but  this  is  not  usual  as  the 
work  can  frequently  be  set  at  such  an  angle  that  tlie 
tapered  surface  to  be  machined  will  be  in  the  same 
plane  as  the  top  of  the  table.   Spedal  forms  can  be 

aoo 


GBNBBATING  AND  FOEMINa  ATTACHMENTS  201 

• 

machined  on  a  planer  by  means  of  a  forming  attach- 
ment which  controls  the  movement  of  the  tool  on  the 
rail.  In  milling  machine  work  it  is  seldom  that  an 
attachment  to  produce  contours  is  required.  The 
form  of  the  piece  to  be  milled  can  be  easily  generated 
on  a  profiler  by  suitable  forming  plates.  It  is  en- 
tirely possible,  however,  to  generate  simple  forms  on 
a  milling  machine  by  the  application  of  a  proper 
fixture  and  a  suitable  forming  plate.  These  several 
machined  are  so  seldom  used  for  forming  that  we 
have  only  the  proposition  of  forming  as  applied  to 
the  engine  lathe,  turret  lathe,  and  vertical  boring 
mill  to  consider.  Therefore,  as  these  three  machines 
are  most  commonly  used  for  work  of  a  cylindrical 
nature,  the  attachments  described  are  particularly 
applicable  to  this  class. 

Simple  Radius  Generating  Attachment.— The  en- 
gine lathe  is  frequently  used  either  by  the  applica- 
tion of  a  forming  attachment  at  the  back  of  the  lathe 
or  by  some  special  arrangement  applied  in  a  suitable 
manner.  The  construction  of  any  such  attachment 
depends  somewhat  upon  the  work  to  be  machined. 
Standard  forming  attachments  applied  to  the  rear 
of  the  machine  can  be  obtained  from  manufacturers 
of  certain  engine  lathes;  but  as  these  attachments 
are  generally  designed  to  operate  longitudinally  along 
the  work,  other  arrangements  are  necessary  when  it 
is  desired  to  generate  a  form  on  the  end  of  a  cylindrical 
piece. 

An  example  of  the  latter  is  shown  in  Figure  90, 
where  an  arrangement  for  generating  a  radius  on 
the  end  of  the  piston  is  seen  at  A.  It  will  be  noticed 


202 


TOOLS  AND  PATTEfiNS 


-  D 


o 

that  tbe  end  of  the  work  is  formed  to  a  perfect 
radius,  and  also  that  the  surface  is  so  large  that  it 
could  not  properly  be  formed  with  a  single  tool.  The 
application  of  the  attachment  to  the  lathe  made  it 
possible  to  generate  the  radius  shown  in  a  short 
time;  furthermore  the  attachment  itself  was  compar- 


GENERATING  AND  FOEMING  ATTACHMENTS  203 


atively  inexpensive.  The  design  was  such  that  con- 
siderable flexibility  was  possible,  both  in  the  length 
of  the  radius  and  in  its  position  with  relation  to  the 
center  of  the  spindle. 

The  construction  of  the  attachment  is  simple;  a 
special  block,  B,  is  supplied  with  a  swivel  top,  C, 
the  upper  part  of  which  was  dovetailed  at  D.  The 
tool-block,  L,  was  furnished  with  a  tool,  E,  for  cut- 
tmg  the  correct  form.  A  special  form  of  bracket,  F, 
is  fastened  to  the  carriage  as  indicated,  and  a  T-slot, 
G,  is  cut  in  it  to  provide  for  transverse  adjustment 
of  the  pivot,  H.  The  arm,  K,  swings  on  this  pivot, 
and  is  attached  to  the  tool-block,  L.  Thus  it  will 
be  seen  that  as  the  cross  feed  of  the  carriage  is 
operated,  the  tool,  E,  will  be  constrained  to  follow 
the  path  indicated  by  the  dotted  line,  M;  except  that 
it  can  be  moved  radially  as  permitted  in  the  tool- 
block  so  as  to  obtain  radii  of  different  lengths,  if 
desired,  and  also  to  compensate  for  re-grinding  the 
tool  when  it  becomes  worn. 

The  attachment  shown  was  designed  by  me  a  num- 
ber of  years  ago  for  an  automobile  plant  in  Massa- 
chusetts, and  since  that  time  I  have  used  the  same 
idea  in  several  other  cases  to  good  advantage.  The 
principal  value  of  this  attachment  is  that  it  can  be 
made  up  so  cheaply.  In  addition,  it  does  the  work 
required  of  it  with  practically  no  attention  on  the 
part  of  the  operator,  and  the  results  produced  give 
excellent  satisfaction. 

Kadins  Forming  Attachment  for  Gmwaisig  Ptd- 
leys. — The  ordinary  cast-iron  pulley,  so  largely  used 
^  machine  work,  has  a    crown"  or  radius  on  the 


204 


TOOLS  AND  PATTJBKNS 


face  to  which  the  belt  is  appUed,  the  purpose  of 
which  is  to  keep  the  belt  from  running  off.  The 
metal  in  the  pulley  at  the  point  which  is  crowned 
IS  usuaUy  thin,  and  consequently  cannot  be  formed 
with  a  wide  tool  of  the  proper  shape  to  good  advan- 
tage. In  machining  these  surfaces  it  is  therefore 
necessary  to  generate  the  form  by  means  of  a  form- 
ing  attachment. 

In  the  instance  shown  in  Figure  91,  the  attachment 
was  so  made  that  two  pulleys  could  be  crowned  at 
the  same  time  with  the  two  tools  indicated  at  A  in 
the  upper  part  of  the  iUnstration.    The  work,  B 
shown  in  the  lower  part  of  the  figure,  is  held  on  an 
arbor,  C,  and  driven  by  means  of  the  driver,  D,  ex- 
tending through  the  face-plate  and  between  the 
spokes  of  the  pnUeys,  as  indicated.  This  attachment 
was  apphed  to  an  old-style  lathe,  and  the  necessary 
movement  was  imparted  to  the  tool-block,  E,  by 
naeans  of  the  rod,  F,  passing  completely  through  to 
the  back  of  the  lathe  as  shown.   A  roller,  Q,  made 
contact  with  the  forming  plate,  H,  and  was  held  in 
place  by  means  of  the  spring,  K.    The  bracket,  L, 
was  fastened  to  the  back  of  the  kthe  carriage  and 
was  simply  used  to  form  a  thrust  surface  for  the 
spring.  It  wai  be  seen  that  as  the  carriage  is  trav 
ersed  longitudinally,  the  two  tools  will  follow  the 
form  indicated  at  H,  thus  generating  the  desired 
surface. 

If  an  engme  lafhe  is  furnished  with  a  forming 
attachment,  work  of  the  character  shown  in  Figure 
91  can  be  more  easily  handled  by  the  application 
of  a  snitable  forming  plate  to  the  forming  slide  at 


PIG.  91.    PLiAN  AND  ELEVATION  OF  A  RADIUS-FORMING  ATTACH- 
MENT FOR  CROWNING  PULLEYS 


the  rear  of  the  machine.  But  the  general  construc- 
tion of  attachments  of  this  kind  is  similar  to  the 
one  shown.  Many  varieties  of  forms  can  be  generated 
%  means  of  forming  attachments  on  the  engine 


206 


TOOLS  AND  PATTERNS 


lathe;  it  is  only  necessary  to  provide  a  plate  to  suit 
any  given  case. 

Piston  Forming  and  Grooving  Attachment.— As 
aitmniiMle  pistons  are  produced  in  large  lots,  every 
effort  is  made  to  design  the  various  tools  used  in 
the  manufacture,  so  as  to  provide  maximum  produc- 
tion. And  as  the  piston  of  an  antomobile  is  a  vital 
part  of  the  motor,  the  greatest  care  is  nsed  in  the 
mannfactore  to  insure  uniformity  and  accuracy. 

Turret  lathes  are  largely  used  for  work  of  this 
character,  and  attachments  are  frequently  applied  for 
combining  several  operations  in  one.  An  excellent 
example  of  a  forming  attachment  which  is  combined 
with  two  equipments  for  grooving  the  piston,  is 
shown  in  Figure  92.  A  plan  view  looking  down  upon 
the  machine  is  shown  in  order  to  make  the  manner 
of  operation  more  apparent. 

The  turret  of  the  machine  is  used  simultaneously 
with  the  tool  shown  in  the  plan  view,  but  as  the 
turret  tools  have  nothing  to  do  with  the  forming 
attachment,  it  would  be  confusing  to  show  them  here. 
The  piston  in  this  case  is  held  on  a  special  chuck, 
A,  this  chuck  being  somewhat  similar  to  that  de- 
scribed in  Chapter  Xm,  Mgure  86.  The  work  to 
be  done  is  the  forming  of  the  ends  of  the  piston,  B, 
to  the  required  radius,  and  simultaneously  to  make 
the  annular  grooves,  C  and  D. 

In  the  first  place,  the  cross-slide  is  furnished  with 
a  si>ecial  block,  dovetailed  to  receive  the  sliding 
member  which  is  carried  under  the  block  that  holds 
the  grooving  tool  for  tl^  surfaces  C  and  D.  The 
dovetailed  slide,  E,  has  a  roller  at  F,  which  is  guided 


GENEEATINa  AND  FORMING  ATTACHMENTS  207 


no.  92.    FfSfOH  lORMINO  AND  OlIOOVINO  ATFACHMENT 


by  the  forming  plate  at  G  and  H,  so  that  the  proper 
form  is  described  on  the  end  of  the  piston,  B.  It  will 
be  seen  that  as  the  cross-slide  feed  is  engaged,  the 
tool  for  turning  the  ends  of  the  piston  at  B  travels 
across  the  lathe  carriage  in  the  path  directed  by  the 
forming  plates.  At  the  same  time,  the  grooving  tools 
are  slowly  moving  forward,  illitil  they  reach  tho 
outside  of  the  piston  and  begin  to  cut.  At  this  time 
the  operator  changes  the  feed  to  a  very  slow  one,  so 
that  the  grooving  tools  cut  only  a  little  at  a  time 
and  do  not  have  any  tendency  to  chatter.  The  feed 
for  a  cut  of  this  kind  on  any  kind  of  a  job  must  be  slow, 
to  produce  good  results,  as  the  cutting  action  of  a 

grooving  tool  is  not  very  good. 


208 


TOOLS  AND  PATTERNS 


It  is  obvious  that  any  such  equipment  as  the  one 
described  herewith  would  only  be  warranted  when 
high  production  is  desired.  Attachments  of  this 
kind,  however,  are  applicable  to  many  varieties  of 
work,  and  combinations  of  tools  can  be  made  to  cover 
many  different  cases.  The  number  of  pieces  to  he 
machined  must  always  be  considered  when  designing 
any  sort  of  special  equipment,  in  order  that  the  ex- 
pense may  be  proportional  to  the  production. 

Angiilar  Qfflwmting  CroM-Slide.— For  inishing  the 
faces  on  large  ring  gears,  the  angular  cut  across  the 
face  of  the  gear  usually  requires  a  special  forming 
attachment  or  special  equipment  of  some  character. 
It  is  entirely  possible  to  machine  work  of  this  kind 
by  means  of  a  forming  attachment  similar  to  the  one 
indicated  in  Figure  92,  but,  of  course,  it  would  be 
necessary  to  make  the  forming  plates  to  the  correct 
angle  of  the  bevel  on  the  face  of  the  gear. 

A  more  convenient  attachment  for  either  an  engine 
lathe  or  a  turret  lathe  can  be  made  up,  as  shown  in 
figure  d3.  This  is  a  special  swivel  cross-slide,  and 
is  designed  to  take  the  place  of  the  regular  cross- 
slide  on  the  machine,  which  must  be  removed  to 
allow  the  swivel  slide  to  be  put  in  position.  The 
particular  advantage  of  a  cross^lide  of  this  char- 
cater  is  that  it  can  be  swung  radially  about  the  cen- 
ter, A,  to  any  angle  within  its  capacity.  The  ring 
gear,  shown  at  B  in  this  instance,  is  to  be  machined 
along  the  face,  C.  The  tool-block,  D,  on  the  swivel 
cross-slide  is  furnished  with  two  tools,  as  indicated, 
for  roughing  and  finishing  this  angular  plate,  which 
are  set  far  enough  apart  so  that  the  roughing  tool 


GENERATING  AND  FORMING  ATTACHMENTS  209 


r 


K 


•B 


res  rr-P 

u 

aQQaDQQQDaQQU 

1 

VIO^  d3.    SPECIAL  SWIVEL  CBOSS-SLUIE  Wm  A  TUREET  LATHE 

completes  its  work  before  the  finishing  tool  starts 
on  the  face  of  the  gear. 

A  swivel  cross-slide  is  not  by  any  means  a  cheap 
attachment,  but  its  usefulness  and  flexibility  is  such 
that  it  can  be  used  advantageously  on  many  kinds 
of  work  requiring  an  angular  generating  device. 
Even  though  the  attachment  is  rather  expensive, 
the  construction  is  simple  and  it  is  not  likely  to  get 
out  of  order.  The  feed  screw  which  operates  the 
slide  is  controlled  by  a  ]f>air  of  bevel  pinions  at  the 
center  which  are  always  in  mesh  no  matter  what  the 
angle  of  the  slide  may  be.  A  suitable  knock-off  can 
be  easily  provided  to  stop  the  cutting  action  at  any 
desired  point. 

Eccentric  Turning  Device  for  Packing  Bings.— 

^^cking  rings  for  automobile  motors  are  frequently 


210 


TOOLS  AND  PATTERNS 


Wm.  04.    ECCENTEIC  TUBMINQ  DEVICE  WOB,  PACKING  RINGS 


made  eccentric,  and  it  is  a  decided  advantage  to  be 
able  to  bore  the  inside  of  the  ring  and  turn  it  eccen- 
tric at  the  same  time.  For  this  purpose,  several 
manufaetiirers  of  turret  lathes  have  developed  equip- 
ment to  apply  to  their  own  product.  One  such  is 
shown  in  Figure  94— -the  eccentric  turning  and  bor- 
ing attachment  for  a  turret'  lathe,  manufactured  and 
patented  by  Pratt  ft  Whitney  Co. 

The  work,  A,  in  the  drawing,  is  held  by  chuck 
jaws,  B,  in  a  three-jawed  gear  scroll  chuck,  the  face- 
plate of  which  forms  a  ring  gear  at  C,  and  drives 
another  gear  of  equal  size,  D.  The  latter  gear  is 
mounted  on  a  shaft,  splined  at  E,  and  carried  by  a 


GENERATING  AND  FORMING  ATTACHMENTS  211 


bracket,  F,  on  the  spindle  cap  of  the  machine.  A 
supplementary  bracket,  G,  is  mounted  on  the  turret 
and  carries  a  slide,  H,  in  which  the  tool,  K,  is 
mounted.  This  tool  is  used  for  turning  the  outside 
of  the  casting,  A,  eccentric  to  the  inside.  The  slide, 
H,  is  held  by  the  pressure  of  a  stifif  spring  against  a 
cam,  shown  at  L.  As  the  work  revolves,  the  shaft 
on  which  the  cam,  L,  is  mounted  revolves  at  exactly 
the  same  speed.  And  as  the  cam  revolves,  it  bears 
against  a  small  roller,  M,  mounted  in  the  slide,  so 
that  it  moves  the  tool,  K,  continually  in  and  out  to 
form  an  eccentric  on  the  outside  of  the  work.  Simul- 
taneously with  the  turning  of  the  outside  of  the  pot, 
a  boring  bar,  N,  having  a  tool,  0,  is  used  to  bore  the 
inside  of  the  ring.  Coincident  with  the  action  of  the 
boring  and  turning  tool,  the  tool-block,  P,  moves 
transversely,  so  that  the  gang  of  tools  mounted  on  it 
cut  off  the  packing  rings  one  by  one. 

This  is  J  excellent  example  of  the  application  of 
special  attachments  to  a  ttirret  lathe,  and  indicates 
the  possibilities  of  this  class  of  machine  in  manu- 
facturing processes. 

Bevel  Oenmtting  Attachment  for  a  Turret  Lathe. — 
The  possibilities  of  the  horizontal  turret  lathe  are 
little  appreciated  by  the  average  manufacturer,  and 
it  is  remarkable  how  poor  a  showing  some  of  these 
Mgh-capacity  machines  are  making  in  many  factories 
simply  because  tool  designers  are  not  as  bold  in  de- 
signs as  they  might  be.  For  bevel  pinions,  and  other 
angular  work  of  similar  character  in  which  the  angle 
IS  less  than  40  degrees  on  one  side  of  the  center  line 
of  the  work,  a  generating  attachment  for  a  hori- 


212 


TOOLS  AND  PATTERNS 


mmial  turret  lathe  may  be  made  that  will  handle  a 
wide  variety  of  work.   Such  an  attachment  is  shown 
in  Figure  95.   The  work,  A,  is  held  on  a  special  form 
of  arbor  where  the  pilot,  B,  enters  a  bushing,  C,  in 
Ije  face  of  the  attachment  and  makes  the  probabil- 
ity of  chatter  very  remote.    The  turret  of  the  ma- 
chine IS  furnished  with  a  bracket  fastened  against 
one  of  the  turret  faces,  as  shown  at  D.  This  extends 
OBt  and  overhangs  the  turret  and  has  a  steel  pilot, 
^,  at  Its  forward  end,  which  is  guided  in  a  bushing, 
F,  supported  by  the  bracket,  a  This  bracket  in  turn 
IS  fastened  to  tie  spindle  cap,  or  to  some  part  of  the 
head  construction  which  is  sufficiently  massive  to 
permit  its  being  used  as  a  support.   This  portion  of 
the  design  depends  largely  upon  the  type  of  turret 
lathe  to  which  it  is  to  be  applied. 
The  bracket,  B,  that  is  fastened  to  the  turret  face, 


GENERATING  AND  FORMING  ATTACHMENTS  213 


is  furnished  with  a  special  slide,  H,  to  which  tool- 
blocks,  snch  as  that  shown  at  K,  can  be  readily  ap- 
plied. These  tool-blocks  may  have  one  or  more  tools 
in  them  according  to  the  work  for  which  they  are 
intended.  The  slide  itself  is  free  to  move  up  and 
down  as  held  by  the  straps,  L.  The  back  of  the  slide 
is  furnished  with  a  block,  M,  that  is  free  to  swivel. 
A  powerful  spring,  adjusted  by  means  of  the  screw 
shown  at  M,  holds  the  entire  slide  up  until  the  swivel 
block  strikes  the  bevel  indicated  at  O.  This  bevel 
is  cut  on  a  long  rectangular  bar  of  steel,  P,  properly 
fitted  to  a  slot  in  the  fixture.  The  angle  of  the  bevel 
is  made  according  to  the  work  to  be  done,  but  any 
number  of  bars  may  be  made  np  for  different  bevels, 
and  they  can  be  replaced  and  snbstituted  one  for  the 
other  in  a  moment's  time. 

The  action  of  this  device  is  extremely  satisfactory, 
and  its  adaptability  iis  such  that  it  can  be  applied 
to  a  wide  variety  of  work.  In  operation,  the  end 
of  the  tapered  bar  (which  is  guided  in  the  bracket 
on  the  headstock)  comes  against  a  stop  (not  shown) 
before  the  cntting  action  of  the  tool,  Q,  commences. 
As  the  tapered  bar  does  not  move  after  it  has  been 
brought  to  the  stop,  it  is  obvious  that  the  entire 
taper-turning  device  moves  forward  along  the  taper 
bar,  and  that  the  swivel  block,  M,  follows  the  angle, 
0,  on  the  tapered  bar  as  it  is  constrained  to  do  by 
the  swing  at  the  back  of  the  slide.  The  tool,  there- 
fore, follows  the  same  angle,  and  generates  the  cor- 
rect taper  on  the  work. 

After  the  work  has  been  finished,  the  entire  mech- 
anism is  withdrawn  by  a  backward  movement  of  the 


214 


TOOLS  AND  PATTERNS 


tnrret,  and  any  other  tools  which  are  on  the  turret 
in  other  positions  can  be  brought  into  action.  After 
tne  worlc  has  been  done  on  one  piece,  another  one  is 
pot  in  position  on  the  arbor,  and  the  tnrret  is  in- 
dexed to  Its  original  position.  After  this  has  been 
done,  the  lever,  R,  is  pulled  forward  to  throw  the 
tapered  bar  ahead  into  its  original  position  ready 
for  uie  new  job  of  work. 

An  equipment  of  this  kind  may  be  made  up  with 
two  attachments,  one  of  which  can  be  used  for  rough- 
ing and  the  other  for  finishing.  These  two  attach- 
ments can  be  on  opposite  sides  of  the  turret  and  may 
be  tied  together  by  means  of  a  suitable  tie-bracket, 
such  as  that  shown  at  S.  I  have  designed  several 
equipments  of  this  kind  for  bevel  gear  work  and 
other  ai^nlar  work,  and  have  found  them  very  satis- 
factory m  action. 

Radius  Generating  Attachment  for  a  Vertical  Turret 
Lathe.— The  Bullard  vertical  turret  lathe  is  adaptable 
in  many  ways:   By  the  aid  of  forming  attachments 
almost  any  kind  of  shape  may  be  generated,  and  the 
machine  is  of  such  rigidity  that  the  heaviest  cut  can 
be  taken  with  impunity.   Incidentally,  in  regard  to 
tte  powOT  of  the  machine„the  story  is  told  that  upon 
being  asked  by  a  prospective  customer,  "How  manv 
machines  can  be  handled  by  one  man,"  Mr.  Bullard 
repUed,  "It  takes  two  men  to  operate  one  machine, 
one  to  handle  the  machine  and  the  other  to  carry 
away  the  chips." 

The  simple  attachment  for  this  type  of  machine, 
shown  ,n  Figure  96,  is  for  forming  or  generating 
a  radius  on  the  surface  of  the  large  pulley,  A.  The 


GBNEaATING  AND  FORMING  ATTACHMENTS  215 


FIG.  96.   BADIUS  GENERATING  ATTACHMENT  FOR  FACINO  A  Pni.L£Y 
ON  THE  BULLARD  VERTICAL  TURRET  LATHE 


forming  or  generating  is  accomplished  by  means  of 
the  side  head  with  the  tool  shown  at  B,  and  attach- 
ments, consisting  of  a  couple  of  brackets,  C  and  D, 
are  attached  to  the  column  of  the  machine.  These 
brackets  support  a  slotted  plate,  E,  by  means  of  the 
bars,  F  and  G,  which  are  adjustable  vertically.  The 
side  head  is  provided  with  a  T-slot,  H,  in  which  a 
link  is  pivoted,  as  shown  at  E.  The  radius  of  the 
link  determines  the  radius  to  be  generated  by  the 
tool  at  B,  and  as  the  link  is  of  the  very  simplest 
constraction  it  will  be  seen  that  different  radii  can 


216 


TOOLS  AND  PATTERNS 


be  readily  established  by  simply  providing  an  extra 
link  ot  the  desired  length.  The  plate,  E  being 
slotted  at  L,  aUows  the  link  to  be  fastened  'at  any 
deared  point  in  the  slot,  so  as  to  determine  the  exact 
center  from  which  the  radius  is  to  be  described. 
There  IS  httle  eost  connected  with  the  mannfacture  of 
an  attachment  of  this  kind,  and  its  usefulness  and 
adaptability  is  qnite  evident. 

Ansmlar  Generating  Attachment  for  Vertical  Tor- 
ret  Lathe.— To  machine  an  angular  surface,  such  as 
that  shown  at  A,  Figure  97,  on  work  of  large  size, 
a  Bullard  vertical  turret  lathe  may  be  supplied  with 
an  Migular  generating  attachment.    Let  it  be  sup- 
posed that  the  bevel  ring  gear  shown  is  to  be  ma- 
chined along  the  surface,  A,  with  an  attachment 
mch  as  that  indicated  in  the  illustration.   The  tool, 
B,  m  this  case  is  held  in  the  turret  of  the  side  head, 
and  angular  motion  is  obtained  by  means  of  the 
roller,  D,  which  bears  against  the  angular  plate,  C. 
The  angular  plate  is  fastened  to  the  side-head  ram 
and  IS  adjustable  along  the  T-slot,  X.  The  roller,  D, 
IS  also  adjustable  up  or  down  in  the  slot  shown  in 
the  vertical  plate,  B.   Provision  for  quick  removal 
of  the  roller  is  made  in  the  large  holes  at  each  end 
of  the  slot.   The  slotted  plate  is  supported  in  much 
the  same  manner  as  that  shown  in  Figure  96  By 
means  of  a  forming  plate  in  place  of  the  angular 
plate,  this  attachment  may  be  used  for  forming  differ- 
ent shapes  if  desired,  and  the  entire  attachment  is 
sufficiently  flexible  to  handle  work  with  quite  wide 
variations.    When  the  vertical  turret  lathe  is  used 
for  heavy  manufiicturing  in  quantities,  an  attachment 


GENERATING  AND  FORMING  ATTACHMENTS  217 


no.  97.    ANOULAK  QENEIUTINO  ATTACHMENT 


of  this  kind  may  be  applied  with  excellent  results. 

lutemal  Sadius  Boring  Attachment.— It  is  occa- 
sionally necessary  to  mach|BM||,  inside  radius  on  a 

piece  of  work,  and  although  conditions  reqniring 

such  an  operation  are  rather  rare,  **it  is  the  unex- 
pected that  always  happens/' 


218 


TOOLS  AND  PATTERNS 


1 

5-— J 

O  O  o 

*m«a    nWaWAL-RAMTO  BORING  ATTACmm^ 

SdTL  t^.^^^'hined  to  the  shape  indicated 

St    Th  ^^^^      ^  ^^^«<^  turret 

lathe    The  attachment  shown,  made  up  for  the  work 

or  the  nature  indicated  several  years  ago  with  ex- 

1?^^  ^  self-contained  in  the  bar,  B. 

Thi.  bar  IS  located  in  the  turret  of  the  machine  and 
IS  of  massive  proportions  so  that  it  may  be  rigid 

«^^tted  to  receive 

a  swiveled  toolholder,  carrying  at  each      the  tools, 


GBNBRATINa  AND  FORMING  ATTACHMENTS  219 

C  and  B,  set  to  cut  the  same  radius  from  the  center 
of  the  bar.  A  link  motion  allows  the  lug  at  the  end, 
E,  to  travel  radially  when  it  is  pushed  downward 
by  the  sliding  block,  F,  operated  by  a  special  rec- 
tangular piece,  G,  in  the  side-head  turret  of  the  ma- 
chine. It  will  be  seen  that  when  the  side-head  down- 
feed  is  started,  the  action  of  the  sliding  block  causes 
the  cutting  tools,  C  and  D,  to  describe  an.  arc,  thus 
generating  the  inside  radius.  Bigidity  of  the  bar  is 
assured  by  the  pilot,  H,  which  enters  a  bushing  in 
the  center  of  the  table  as  indicated. 

This  attachment  is  decidedly  special,  and  was  con- 
structed for  a  particular  piece  of  work  requiring  con- 
siderable accuracy.  It  is  not  to  be  supposed  that 
such  an  equipment  will  be  frequently  called  for,  but 
conditions  may  arise  in  any  factory  which  may  neces- 
sitate some  arrangement  for  internal  radius  boring, 
in  which  event  an  equipment  of  this  kind  would  be 
of  the  greatest  use. 


CHAPTER  XV 


.  VEETICAL  BOBINQ  MILL  PIXTUBES 

Fnadamatil  Oonstmetion  Features—Fixtures  dp 
«gned  for  vertical  boring  n,i„s  are  natu^dlv 
heavier  m  construction  than  those  used"  „  a 

perfectly  logica    because  the  work  done  on  a  ver- 
bonng  rmll  requires  heavier  speeds  and  fel 
than  the  class  of  work  done  on  tlTe  smfllil.  ^ 
Ughter  ujachines..  While  a  vertical  bor^^^^^^^ 

nsed  for  machining  many  of  the  same  stvles  of 

sr^^r^'r-'r^'  z  *  '•--tauurrtt,: 

the  difference  in  the  work,  however,  is  one  of  size- 
STollr^"*'"'"  "  "^"^"^^  ^ 

tion"wiiw:  V  "^^T  mentioned  in  connec- 

iat  Thf  wI'J  • T*''''  ''"""^  "'i"-  That  is 
it  t  Inf         "  «  horizontal  plane,  and 

fix  urrl"r'.''^'^'  counterbalance  any 

if  the  "".odf  shaped  piece,  as  it  would  he 

m?it  ha,  th«      .  "°  »  ^«rtical  boring 

ti^  lit  '•'^        of  rotation  in  a  ve" 

tical  plane,  and  the  work  revolves  horizontally; 

220  ' 


221 


while  on  the  horizontal  turret  lathe  the  center  line 
or  axis  of  rotation  is  in  a  Iiorizontal  plane,  and  the 
work  revolves  vertically. 

In  vertical  boring  mill  practice,  therefore,  the 
work  may  be  laid  down  on  the  table  of  the  machine 
and  can  readily  be  clamped  down  to  it.  The  weight 
of  the  piece  really  assists  in  holding  it;  and  the  only 
thing  necessary  in  the  clamping  device  is  that  pres- 
sure enough  be  applied  to  keep  the  work  from  slipr 
ping  under  the  pressure  of  the  cut.  It  must  also 
be  remembered  that  the  cuts  taken  on  these  heavy 
boring  milte,  are  greatly  in  excess  of  those  used  on 
horizontal  machines. 

For  many  kinds  of  heavy  manufacturing  work  the 
vertical  boring  mill  or  vertical  turret  lathe  can  be 
used  to  freat  advantage,  and  the  massive  construc- 
tion of  these  machines  permits  work  to  be  done 
within  close  limits  of  accuracy.  Furthermore,  ma- 
chines of  this  type  can  be  easily  set  up  with  a  com- 
paratively small  outlay  for  tool  equipment,  so  that 
although  tlie  first  cost  of  the  machines  is  rather  largOi 
the  productive  efficiency  is  extremely  high. 

Vertical  Boring  Mill  Fiztare  for  Thin  Work.— 

The  problem  of  holding  and  machining  a  piece  of 
thin  work  is  always  more  or  less  difficult,  because 
it  is  not  easy  to  hold  the  work  without  distorting  it, 
and  in  addition,  the  work  is  likely  to  be  sprung  out 
ef  shape  by  the  pressure  of  tie  cut  in  machining. 
It  is  necessary,  therefore,  in  designing  a  method 
for  holding  a  piece  of  thin  work,  to  strive  to  prevent 
both  distortion  from  tlie  holding  device  and  distor- 
tion from  the  pressure  of  the  cutting  tool. 


™.  99.    METHOD  OF  HOU)INO  ram  WOIIK  W  A  VIBTKUL 


VERTICAL  BORING  MILL  FIXTURES  223 


An  excellent  example  of  a  piece  of  work  of  thin 
section  to  be  machined  on  the  vertical  boring  mill 
is  shown  in  Figure  99.  The  method  nsed  for  hold- 
ing  this  piece  and  supporting  it  while  machining, 
can  be  applied  to  a  number  of  cases  of  similar  char- 
acter with  slight  variations.  The  work  is  large  in 
diMneter,  and  it  is  necessary  to  machine  it  on  the 
surfaces  A,  B,  C,  and  D.  Since  the  web,  B,  is  very 
thin,  it  is  necessary  to  support  this  portion  of  the 
work  to  keep  it  from  swinging  downward  while  the 
cutting  tool  is  in  action.  The  direction  of  the  cut 
is  indicated  by  the  arrows;  and  the  tool  which  is 
used  on  the  portions  B  and  C,  is  shown  at  E  in  the 
side-head  of  the  machine.  The  work  is  laid  down 
upon  a  special  cast-iron  locating  ring,  F,  which  ie 
held  down  by  lugs,  indicated  at  6,  in  the  table  key- 
slots.  The  work  is  centered  by  means  of  the  special 
hook-bolt  jaws,  H,  which  are  soft  and  bored  out  to 
fit  the  outside  of  the  work.  (Incidentally,  the  work 
has  been  finished  on  the  surface,  K,  in  a  previous 
setting.)  The  three  jaws  indicated  are  attached  to 
the  master  jaws  on  the  table  chuck,  as  shown  in  the 
upper  view,  and,  as  the  table  chuck  is  of  the  three- 
jawed  geared  scroll  variety,  the  work  is  readily  cen- 
tered on  the  table.  The  jaws  are  brought  up  very 
lightly  on  the  outside  of  the  work,  so  as  not  to  cause 
any  distortion;  and  after  they  are  brought  in  con- 
tact with  the  work,  the  hook  bolts,  L,  are  tightened 
by  means  of  the  nut,  M,  so  that  the  work  is  gripped 
at  three  points  around  the  circumference  in  much 
the  same  manner  as  though  it  were  held  in  three 
separate  vises.  It  can  be  easily  seen  that  this  method 


224 


TOOIiS  AND  PATTERNS 


of  holding  is  exceptionally  rigid  and  does  not  cause 
distortion  in  the  work.  The  pot,  F,  acts  as  a  locat 
ing  device  to  give  the  correct  height  to  the  work, 
and  at  the  same  time  it  supports  it  against  the 
pressure  of  the  cut. 

Speeial  Tixtme  with  Tapered  Plug  Locater.— It  is 
frequently  necessary  to  locate  a  piece  of  work  on  a 
tapered  hole  that  has  previously  been  machined,  and 
at  the  same  time  to  hold  the  pece  by  means  of 
clamps  on  some  other  portion.  As  it  is  a  difficult 
matter  to  machine  a  tapered  surface  and  a  plane  sur- 
face  so  that  they  will  always  bear  an  exact  relation 
to  each  other,  some  method  of  holding  must  be  used 
which  will  compensate  for  the  variations  between 
the  two  surfaces. 

Let  us  take  as  an  example  of  this  kind  of  work 
the  piece  shown  at  A,  Figure  100.   This  work  is  a 
iywheel  for  an  automobile  engine,  and  it  has  been 
machined  in  a  previous  setting  in  the  tapered  hole,  B, 
and  also  on  surfaces  C,  D,  and  E.  Now  in  order  to 
machine  the  side  of  the  work,  F,  and  the  hub,  G, 
80  that  they  will  be  in  the  correct  relation  to  the 
previously  machined  tapered  hole,  it  is  necessary  to 
locate  the  work  on  a  plug  in  this  tapered  hole.  But 
while  this  location  would  be  all  right,  it  would  not 
be  possible  to  clamp  the  work  easily  without  spring- 
ing it  out  of  shape  if  it  were  to  be  located  only  on 
the  tapered  plug.    The  surface,  D,  then,  must  be 
used  for  attadiing  an  additional  clamp,  but  as  this 
surface  may  vary  slightly  in  its  relation  to  the 
tapered  hole,  any  method  of  clamping  must  be  so 
designed  that  compensation  may  be  made  for  sur- 


VEBTICAIi  BO1IN0  MILL  FIXTURES  225 


no.  100.    BmMNQ  A  PIEGS  OF  WOBK  BY  rrS  TAPEEED  HOU 


face  variations.  This  is  accomplished  by  making 
a  tapered  plug  or  shell,  as  shown  at  H,  and  locating 
this  shell  on  a  threaded  stud,  K,  set  in  the  center 
hole  in  the  table.  The  upper  end  of  the  tapered 
shell  is  squared  out  to  receive  the  special  socket 
wrench,  L,  by  means  of  which  it  is  operated. 


226 


TOOLS  AND  PATTERNS 


The  method  of  using  this  fixture  is  as  follows: 
The  plug  is  lowered  by  means  of  the  screw,  so  that 
the  work  can  slip  onto  it  loosely.  The  clamps,  M, 
which  are  three  in  number,  are  then  set  up  lightly 
on  the  rim,  C.  After  this,  the  socket  wrench,  L,  is 
used  to  screw  the  tapered  bnshing  up  in  the  hole, 
thns  locating  the  work  on  the  tapered  portion.  After 
this  has  been  done  the  clamps  are  tightened  securely, 
and  the  work  is  ready  for  machining. 

Applications  of  this  principle  can  often  be  used 
to  hold  work  of  this  character,  with  various  methods 
of  compensating.  The  tapered  shell  bushing  is  some- 
times  arranged  on  a  spring,  so  that  it  is  self-locat- 
ing. A  method  of  this  kind  is  quite  satisfactory  and 
generally  gives  good  results. 

Ezpandiii;  Arbor  and  Faceplate  for  Vertical  Bor- 
mg  Mill— For  a  piece  of  work  that  has  been  pre- 
viously  machined  and  is  to  be  located  in  the  second 
netting  by  the  previously  machined  surface,  it  is 
necessary  to  make  up  a  locating  fixture.  A  good 
example  of  such  a  fixture  is  shown  in  Figure  101. 
In  this  case  the  work,  which  is  a  double  bevel  gear, 
hm  been  previously  machined  at  A  and  B,  and  on 
the  bevel-gear  faces,  C  and  D.  It  is  necessary  to 
locate  it  for  this  operation  by  means  of  the  hole,  B, 
md,  as  the  work  must  be  very  accurately  done,  an 
expanding  arbor  must  be  used  in  the  hole.  In  con- 
junction with  the  expanding  arbor,  it  is  necessary  to 
prevent  the  work  from  springing  at  the  surfaces  of 
the  outer  bevel-gear  ring,  D. 

A  cast-iron  fixture  body,  E,  is  located  in  the  center 
of  the  table  by  means  of  the  plug,  F,  which  enters 


VBBTICAI4  BOMNa  MILL  FIXTURES  227 


FIG.  101.    PLAN  AND  SECTION  OP  EXPANDING  ARBOR  AND  FACE 
¥UkTE  FOR  VBBTIGAL  BORINO  MILL 


228 


TOOLS  AND  PATTERNS 


the  center  hole.  The  work  is  placed  in  position 
over  the  central  ping  and  drops  down  against  the 
surface,  A,  of  the  fixture.  A  split  ring,  G,  similar 
to  the  type  described  under  the  heading  Split  Ring 
Expanding  Arbor,"  Chapter  XHI,  is  then  expanded 
by  means  of  the  bolt,  H,  thus  giving  the  desired 
centering  action.  The  spring  jacks,  K,  are  now  re- 
leased and  allowed  to  spring  up  against  the  surface, 
D,  after  which  they  are  locked  by  means  of  the  set- 
screws,  L.  The  final  clamping  of  the  work  is  ac- 
complished by  means  of  the  hook-bolts,  M,  which  are 
operated  by  the  bolts,  N. 

The  principle  shown  in  this  fixture  can  be  applied 
to  a  great  variety  of  work,  and  it  can  be  adapted 
to  suit  different  conditions,  both  as  to  the  means 
of  clamping  and  as  to  the  points  on  which  the  work 
is  located.  Any  method  of  clamping  applied  to  a  fix- 
ture which  has  been  previously  machined  must  take 
into  consideration  the  fact  that  no  distortion  can 
be  permitted.  The  use  of  springs  and  spring  jacks 
for  this  purpose  is  common.  Care  must  be  exercised 
that  when  the  set-screws  are  tightened  they  will  not 
force  the  jacks  out  of  position. 

Vertical  Boring-Mill  Fixture  for  a  Fragile  Alumi- 
num Casting.— One  of  the  most  difficult  examples  of 
a  fixture  for  holding  a  piece  of  thin  work  of  irregular 
shape,  and  machining  it  when  held  without  causing 
distortion  in  the  work,  is  shown  in  Figure  102,  at 
A.  In  the  plan  above,  it  will  be  seen  that  the  cast- 
ing has  a  thin  flange  of  approximately  elliptical 
shape  and  the  face  of  this  flange  is  to  be  machined 
m  the  setting  indicated.  In  addition  to  this  the  face, 


VERTICAL  BORING  MILL  FIXTURES  229 


72ZZZZZ 


TO.  102.    PLAN  AND  SECTION  OF  A  VEETICAIi  BORING  Mllli 
FIimJilE  POR  A  WRkQUM  ALUMINUM  CASTING 

B,  located  below  the  snrface  of  the  other  flange, 
must  also  be  f acei**ii  the  same  operation.  The  part 
of  the  flange  indicated  at  A  is  joined  to  the  right- 
hand  portion  of  the  casting,  as  indicated  in  the  sec- 
tional view  below.  The  other  side  of  the  flange,  how- 
ever, at  C,  is  open  and  nnsupported,  making  it  very 
difficult  to  hold  the  piece  without  forcing  the  parts 
out  of  alignment 


230 


TOOLS  AND  PATTEBNS 


This  piece  of  work  is  one  of  the  most  difficult  that 
I  have  ever  encountered,  and  I  give  it  here  simply 
to  show  the  possibilities  of  arranging  clamping  de 
vices  so  that  they  will  not  distort  the  work.  The 
piece  IS  set  up  with  the  boss,  on  the  under  side  of 
^  locating  in  a  V-block  on  the  fixture  base,  and  the 
edge  of  the  adjacent  flange  is  supported  by  the 
spnng  pins  indicated  at  D.    These  spring  pins  are 
locked  by  means  of  the  special  screw,  B.  The  flange 
A,  rests  against  a  knife^dge  locater,  F,  and  is  lightly 
Jami^  by  means  of  swinging  knife-edge  dogs  at 
e  and  H,  while  resting  on  the  pads  shown  at  K 
The  other  side  of  the  flange,  C,  is  simply  a  rim 
which  must  be  held  and  firmly  located  without 
sprmging  it  out  of  position  in  the  slightest  degree 
For  this  purpose,  the  floating  hook-bolt,  shown  at  L 
is  made  in  triplicate.    These  bolts  are  used  in  the 
three  bosses,  M,  N,  and  0,  although  only  one  of  them 
IS  shown  in  the  illustration.   The  action  of  the  hook- 
bolts  IS  such  that  the  work  is  clamped  between  the 
jaws  shown  while  the  entire  mechanism  "floats",  so 
that  It  does  not  strain  the  work.    After  the  hook- 
bolt  IS  tightened,  it  is  locked  in  place  by  means  of 
the  set-screw,  P. 

By  this  method  of  clamping,  any  piece  of  delicate 
sectaon  may  be  clamped  without  causing  distortion. 
Although  the  example  shown  is  a  rare  case,  the  prin- 
ciples involved  in  this  design  can  be  applied  with 
equal  success  to  other  work  of  similar  nature.  It  is 
sufficient  to  say  in  regard  to  the  fixture  mentioned 
that  its  work  was  in  every  way  satisfactory  and  the 

work  was  maduned  without  error. 


VEBTICAIj  BOBINe  MILL  FIXTUEES  231 


Simple  Tiitnre  for  Machining  an  Eeeentrie.— An 

example  of  a  fixture  for  turning  an  eccentric  piece 
was  shown  in  the  group  of  fixtures  in  Chapter  XII, 
but  in  that  case  the  work  was  held  on  a  swinging 
fixture  applied  to  a  horizontal  turret  lathe.  Another 
example  of  an  eccentric  turning  fixture  of  the  in- 
dexing  type,  but  arranged  for  a  vertical  boring  mill, 
is  shown  in  Figure  103.  In  this  case,  the  work  is 
set  up  on  an  indexing  plate,  A,  by  means  of  the 
three  pins,  B,  in  the  flange.  This  indexing  plate  is 
located  eccentrically  on  a  base,  C,  which  is  fastened 
to  the  boring  mill  table,  being  located  on  a  plug,  D, 
in  the  center  hole.  After  the  work  is  set  up  on  the 
pins,  it  is  clamped  in  place  by  means  of  the  three 
hook-bolts  shown  at  E,  these  bolts  being  brought 
down  on  the  flange  as  indicated  in  the  upper  view. 
When  clamped  in  the  position  shown,  the  hole,  F,  is 
bored,  and  then  the  upper  part  of  the  fixture,  A,  is 
swung  around  until  the  center,  G,  takes  the  place 
of  the  hole  previously  machined.  A  locating  pin  is 
provided  at  H  to  give  the  correct  location. 

In  indexing  the  fixture,  the  button  clamps  around 
the  rim,  as  shown  at  K,  and  is  loosened  to  permit 
the  revolution  of  the  portion,  A;  but  when  the  table 
has  been  indexed  to  the  proper  position  these  clamps 
are  again  tightened  before  the  machining  takes 
place.  The  next  operation  on  the  work  is  the  ma- 
chining of  the  eccentric,  L,  when  it  has  been  indexed 
into  the  position  mentioned.  After  this  the  work  can 
he  removed  from  the  fixture  and  another  substituted 
for  it. 

Work  of  this  character  m  frequently  machined  in 


TOOLS  AND  PATTERNS 


MG.  103.    PLAN  AND  SECTION  OF  A  FIXTURE  wm  AN  BOqiNTOIC 

PIECE  OP  WORK 

two  settings,  and  no  attempt  is  made  to  make  an 
indexing  fixture  sneh  as  that  shown.  In  such  an 
event  the  ordinaiy  method  of  procedure  is  to  bore 
the  hole  first  and  then  locate  the  work  on  another 
fixture  on  a  atnd  set  eccentrically  to  the  center  for 


VEETICAL  BORING  MILL  FIXTURES  233 

the  turning  of  the  eccentric  surface,  L.  The  matter 
||»iesigning  a  fixture  for  a  piece  of  work  of  this 
kind  is  dependent  entirely  upon  the  number  of  pieces 
to  be  machined  and  the  accuracy  required  in  the 
finished  product.  Application  of  this  principle  may 
be  made  to  many  varieties  of  work  where  two  sur- 
faces are  machined  eccentric  to  each  other. 

Sliding  Fixture  for  Boring  a  Pair  of  Cylinders.— 
When  a  pair  of  cylinders,  such  as  those  shown  in 
Figure  104,  at  A  and  B,  are  to  be  bored  and  faced 
on  a  vertical  boring  mill,  the  work  must  be  handled 
either  by  means  of  two  settings,  or  by  an  eccentric 
or  sliding  fixture.  If  two  settings  are  to  be  used, 
the  ordinary  method  of  handling  is  to  machine  one 
of  the  cylinders  first  and  then  set  it  up  on  a  stud 
eccentric  to  the  center  of  the  table  at  the  correct 
distance  to  bring  the  center  of  the  second  cylinder 
into  position  for  boring.  For  rapid  production,  how- 
ever,  a  sliding  fixture  or  one  having  an  eccentric 
movement  can  be  designed,  so  that  the  work  can 
all  be  handled  at  one  setting,  thus  saving  consider- 
able time  in  the  machining  and  in  the  handling  of 
the  work. 

The  device  shown  in  Figure  104  consists  of  a 
base  plate,  C,  which  is  fastened  to  the  table  and  is 
centrally  located  by  means  of  the  plug,  D.  The  base 
plate  is  held  by  means  of  the  bolt,  E,  in  the  table 
T-slot  as  indicated.  Mounted  on  the  base  plate,  C, 
is  a  dovetailed  slide,  F,  on  which  suitable  clamps,  G, 
are  provided  to  hold  the  work.  A  sectional  view 
taken  through  the  base  is  shown  at  H.  Along  eacn 
side  of  the  sliding  members  are  two  handles,  K,  for 


TOOLS  AND  PATTERNS 


104.  BmmQ  wnmjm  worn  mmmQ  a  pais  ov  ctmndebs 


VBBTICAL  BOMNO  i!mlPIXTUBES  235 


the  purpose  of  locking  the  sliding  fixtures  in  any 
desired  position.  After  one  of  the  holes  has  been 
bored,  the  handles  are  unscrewed  and  the  fixture  is 
push^  over  until  the  second  cylinder  is  under  the 
center  of  the  spindle,  the  correct  location  being  as- 
sured by  means  of  a  taper  pin,  L.  When  the  de- 
sired position  has  been  reached,  the  levers,  K,  are 
again  tightened,  and  the  second  cylinder  may  be 
bored  in  exactly  the  same  manner  as  the  first. 

Threaded  Knock-off  Arbor  for  Vertical  Boring 
Mill.— The  work  shown  at  A,  Figure  105,  is  a  large 
head  used  for  a  rock  drill.  The  piece  is  made  of 
chrome-nickel  steel  which  is  extremely  hard  to  cut. 
The  work  has  been  previously  machined  on  the  in- 
side surfaces,  B,  and  has  been  threaded  at  C  as 
indicated.  It  is  necessary  to  machine  the  outside 
tapered  surfaces,  A  and  B,  in  another  setting,  and 
these  surfaces  must  be  in  correct  relationship  to  that 
previously  threaded  inside  of  the  work.  A  knock-off 
arbor  was  therefore  suggested,  such  as  that  indicated 
in  the  illustration. 

This  work  was  to  be  done  on  a  vertical  boring  mill, 
and  accuracy  was  an  essential  point.  The  base  of 
the  fixture,  D,  is  located  on  the  table  of  the  machine 
and  is  held  in  place  by  means  of  the  bolts,  E,  which 
pass  through  the  T-slot  in  the  table  and  are  clamped 
by  means  of  the  shoes  shown  at  P.  The  location  of 
the  plate  is  obtained  by  means  of  the  threaded  stud 
which  is  ground  to  a  fit  at  G  in  the  central  hole  of 
the  table.  The  right-hand  threaded  arbor,  H,  is 
made  at  the  upper  part,Vso  that  the  thread  corre- 
sponds to  the  inside  thread  in  the  work  at  C.  Below 


23i 


TOOLS  AND  PATTERNS 


F-1 


TO.  105.    THEEADB©  KNOCK-OFF  ABBOB  WOR  A  VEBflGAL 

BORINO  MILL 


this  a  left-hand  thread  is  cut  at  K.  The  lower  part 
of  the  arbor  is  provided  with  two  pins,  L,  in  order 
to  give  good  driving  properties.  The  knock-off  por- 
tion of  the  arbor  is  shown  at  M,  with  a  left-hand 
thread  to  fit  the  part  K. 

Let  it  be  supposed  that  the  fixture  is  abont  to  be 
loaded  by  attaching  the  piece  A.  At  this  time  tlie 
knock-off  portion,  M,  is  screwed  up  until  it  shoulders 
against  the  portions  N.  The  work,  A,  is  then  screwed 
OB  imtil  it  makes  up  against  the  surface  0.  The 


VERTICAL  BORING  MILL  FIXTUEBS  237 


work  is  now  ready  for  machining,  and  during  the 
action,  because  of  the  pressure  of  the  cut,  the  sur- 
face, 0,  becomes  very  tightly  in  contact  with  the 
knock-off  pad.  After  the  work  has  been  done,  a 
sharp  blow  on  one  of  the  projecting  lugs  of  the 
knock-off,  M,  causes  the  pressure  at  the  point  0  to 
be  relieved,  so  that  the  work  can  be  easily  unscrewed 
from  the  arbor.  The  principles  involved  in  this  arbor 
are  practically  the  same  as  those  described  in  Chap- 
tei  XIII,  under  the  heading  Expanding  Arbor  for 
an  Adjusting  Nut" 


CHAPTBB  XVI 


CHONDING  FIXTURES 

Adaptabili^  of  Cutting  Hxtum.— The  f unctioiis 
of  grinding  as  praetieed  by  manufacturers  in  general 
have  been  taken  up  in  Chapter  VII,  but  the  matter 
of  holding  fixtures  for  the  grinding  operations  has 
not  been  dealt  with  to  any  extent.  As  a  matter  of 
fac^  fixtures  used  for  grinding  purposes  are  very 
similar  to  those  used  in  various  machining  opera- 
tions, although  the  necessity  for  holding  the  piece 
rigidly  is  not  present,  since  the  amount  of  pressure 
exerted  on  the  work  by  the  grinding  operations  is 
nothing  like  as  severe  as  by  the  cutting  operations. 
Many  of  the  fixtures  devised  for  machining  opera- 
tions can  be  used  for  grinding,  but  as  a  rule  grinding 
fixtures  are  considerably  lighter  in  construction  than 
those  used  for  turning  and  facing. 

The  principles  which  apply  to  holding  devices  of 
various  kinds  for  turning  can  be  applied  to  grind- 
ing practice,  with  proper  modifications  to  suit  the 
conditions.  For  example,  there  are  many  cases  where 
a  spring  clamp  can  be  used  for  a  grinding  fixture 
with  excellent  results,  and  yet  such  clamps  would 
not  be  suitable  in  any  way  for  machining  operations 
on  account  of  their  lack  of  holding  power.  The  pull- 
ing action  of  a  grinding  wheel  taking  a  very  light 

288 


eilNDING  FIXTURES 


2S9 


fIG.  106.    METHOD  OF  SETTING  UP  A  GRINDING  MACHINE  FOB 
EXTERNAL  GTMNDRIGAL  GRINDING 

cut  is  nowhere  near  as  severe  as  when  a  cutting  tool 
is  used  on  the  work. 

When  cylindrical  work  is  to  be  ground,  there  is 
seldom  a  need  for  any  sort  of  grinding  fixtures— 
unless  some  portion  of  the  work  is  irregular,  in  which 
case  a  special  method  must  be  used  for  holding.  The 
ordinary  method  of  locating  and  holding  a  piece  of 
cylindrical  work  for  external  grinding  is  illustrated 
in  Figure  106.  The  work,  A,  in  this  case  has  several 
shoulders,  B,  C,  and  D,  which  are  to  be  ground  in 
the  setting  indicated.  The  work  is  located  on  the 
centers  shown  at  E  and  F,  and  is  driven  by  a  dog, 
6.  which  enters  the  driven  faceplate,  H.  While  the 
work  is  in  the  position  indicated,  the  wheel,  K,  is 
traversed  in  the  direction  indicated  by  the  arrows 
until  the  various  diameters  have  been  ground  to  the 
correct  size.  It  will  be  seen  that  no  special  eqnip- 
ment  of  any  kind  is  necessary  in  performing  work  of 
this  character. 


210 


TOOLS  AND  PATTEBNS 


no.  107.    BOTABT  AND  RECTANGULAR  MAGNETIC  CHUCKS 


Magnetic  CQmcks. — ^Frequently,  however,  cylin- 
drical work  requires  special  fixtures,  for  although 
the  portion  which  is  to  be  ground  may  be  cylindrical, 
it  may  happen  that  the  method  of  holding  must  be 
special  in  order  to  accommodate  a  peculiarly  shaped 
piece.  CSiueks,  either  magnetic  or  the  step-chuck 
type,  are  largely  used  for  holding  work  which  is  to 
be  ground.  When  the  work  permits  the  holding 
by  magnetic  chucks,  this  method  is  largely  used  and 
gives  very  satisfactory  results.  Otherwise,  a  step- 
chuck  can  be  arranged  to  handle  the  work. 

A  group  of  magnetic  chucks,  made  by  the  Heald 
Machine  Co.,  is  shown  in  Figure  107.  Those  shown 
at  A  and  B  are  of  the  rotary  t3rpe,  while  those  shown 
at  C,  D,  and  E,  are  of  the  rectangular  type,  not  used 
on  rotary  machines,  but  applied  principaUy  to  sur- 
face grinding.  One  of  the  great  advantages  de- 
rived from  the  use  of  magnetic  chucks  is  the  rapidity 
with  which  the  work  is  applied  to  and  removed  from 
the  chuck.  Another  advantage  lies  in  the  fact  that 
there  is  little  danger  of  distortion  caused  by  an  im- 


GRINDING  FIXTURES 


241 


proper  method  of  clamping.  This  feature  is  par- 
ticularly  noticeable  when  thin  work  is  to  be  ground. 
Still  another  advantage  is  that  a  great  number  of 
pieces  can  be  held  at  the  same  time.  It  is  only  nec- 
essary to  throw  a  switch  in  order  to  apply  the  elec- 
tric current,  magnetize  the  soft  iron  core  of  the 
chuck,  and  hold  rigidly  any  work  on  its  surface. 

The  rotary  chuck,  shown  at  A  and  B,  can  be 
Applied  to  a  horizontal  machine  for  cylindrical 
grinding,  or  to  a  rotary  surface-grinding  ma- 
chine. Piston  rings  or  packing  rings,  for  example, 
are  usually  ground  on  their  edges  on  this  type  of 
chuck.  The  rectangular  type  of  chuck,  shown  at 
C,  D,  and  E,  is  particularly  suited  to  surface  grind- 
ing and  to  milling  or  planing  operations.  In  applica- 
tion they  hold  a  number  of  small  pieces  or  a  single 
piece  of  long  work. 

Many  uses  will  be  found  for  these  chucks  in  a 
manufacturing  establishment,  and  the  type  of  chuck 
most  suited  to  any  man's  work  can  best  be  deter- 
mined by  consultation  with  the  various  manufac- 
turers. Suitable  demagnetizers  are  applied  to  all 
chucks  of  the  magnetic  type,  so  that  after  the  work 
has  been  removed,  no  future  trouble  is  experienced 
from  magnetism  remaining  in  the  work. 

Grindin|l"%izture  for  Universal-Joinl  Part— A 
number  of  pieces  in  an  automobile  are  made  of  alloy 
steel  that  requires  special  methods  of  hardening.  One 
of  these  pieces  is  the  rocker  arm  of  the  universal 
joint,  shown  in  Figure  108  at  A.  This  piece  must  be 
ground  on  the  two  cylindrical  portions  B  and  C,  and 
it  requires  a  special  fixture  as  indicated  at  D.  This 


242 


TOOLS  AND  PATTERNS 


FIG.  108.    FIXTURE  FOB  GRINDING  UNIVERSAL  JOINTS 


fixture  is  not  designed  for  the  purpose  of  holding  the 
work,  but  merely  to  provide  a  means  for  driving 
the  long  end,  A,  and  preventing  vibration  of  the 
work  during  the  process  of  grinding.  Snch  a  fixture 
as  this  can  be  mounted  on  an  adapter  plate,  as  at  E, 
attached  to  the  spindle  of  the  machine  and  rotated. 

The  work  in  Figure  108  is  held  on  the  faceplate, 
and  is  located  on  two  centers,  as  indicated.  A  suit- 
able thumb  screw  is  provided  at  F  on  the  fixture,  so 
that  when  the  work  is  placed  in  position  the  thumb 
screw  can  be  tightened  to  throw  the  work  over 
until  it  strikes  a  stud,  6.  Since  this  fixture  with 
the  work  in  position  is  heavier  on  one  side  than  on 
the  other,  a  cast-iron  lug,  H,  is  applied  to  the  oppo- 
site side,  as  shown,  so  that  the  entire  fixture  can  be 
properly  balanced  before  the  work  is  done.  If  a 
grinding  fixture  of  this  sort  were  to  be  made  up  and 
not  properly  balanced,  the  action  on  the  entire  ma- 
chine would  be  injurious  and  the  work  produced 
would  not  be  true.  It  is  not  only  advisable  but  nec- 
essary to  see  that  any  fixture  used  for  grinding  is 
properly  balanced  to  obtain  the  best  possible  results. 


©BINDING  FIXTURES 


243 


WIQ.  109.    FIXTURE  FOR  GRINDING  PISTONS 


Piston  Grinding  Fixtures.— Manufacturing  prac- 
tice differs  in  regard  to  the  finishing  of  automobile 
engine  pistons,  but  most  makers  finish  the  external 
surface  of  the  piston  by  grinding.  When  this  is  done, 
accuracy  can  be  more  readily  kept  within  the  re- 
quired limits,  and  the  superior  finish  gained  by  the 
grinding  is  an  added  advantage. 

A  fixture  for  holding  an  automobile  piston  while 
grinding  is  shown  in  Figure  109.  In  this  case,  the 
work.  A,  is  located  on  an  arbor,  B,  which  is  drawn 
back  into  a  tapered  hole,  C,  in  a  special  nose  piece, 

D,  which  is  screwed  to  the  end  of  the  last  spindle, 

E.  A  key  to  hold  the  work  on  the  spindle  is  pro- 
vided at  F,  somewhat  unnecessarily  in  the  instance 
shown.  I  say  unnecessarily,  because  the  amount  of 
friction  generated  by  the  grinding  wheel  against  the 
outside  of  the  piston,  A,  could  never  be  sufficient 
to  permit  the  arbor,  B,  to  turn  in  the  tapered  hole, 


TOOLS  AND  PATTEBNS 


especially  when  drawn  back  by  means  of  the  nnt 
and  washer  shown  at  G.  The  end  of  the  piston  is 
given  additional  snpport  by  meeris  of  the  center 
shown  at  H,  this  center  being  in  the  tailstock  of  the 
grinding  machine.  The  method  of  holding  the  pis- 
ton on  the  arbor  is  somewhat  ont  of  the  ordinary 
and  IS  therefore  worthy  of  description. 

The  open  end  of  the  piston  locates  on  the  arbor 
at  K,  and  is  drawn  back  firmly  against  the  shoulder, 
L,  by  means  of  the  rod,  M,  and  the  taper  wedge,  N 
When  the  work  is  placed  in  position,  the  ball-ended 
ping,  0,  is  dropped  through  the  wrist-pin  hole,  P 
passing  through  the  draw-back  rod  as  indicated' 
After  this  has  been  done  the  wedge,  N,  is  pushed 
lightly  into  place  until  the  operating  rod,  M,  draw<! 
Imck  on  the  pin,  0,  to  carry  the  work  up  against 
the  shoulder,  L,  where  it  is  held  firmly.   A  slot  is 
cut  m  the  pin,  0,  as  indicated  at  Q,  so  that  the  re- 
taining pin,  B,  will  prevent  it  from  falling  out  of 
the  work.  The  purpose  of  the  spring  indicated  at  S, 
IS  to  force  out  the  rod,  M,  after  the  work  has  been 
done  and  when  the  wedge,  N,  is  pushed  back.  A 
gnnding  fixture  of  this  sort  can  be  applied  to  many 
varieties  of  work  with  suitable  adaptations  to  con- 
form to  the  style  of  work  to  be  gound. 

iBtenial  Oiiadiag  Hxtmw^-A  Bafl-Bearing  Cage. 
—Let  It  be  assumed  that  the  work  A,  Figure  110,  has 
been  previously  machined  at  all  necessary  points,  has 
subsequently  been  hardened,  and  that  it  is  now  neces- 

in  correct  relation  to  the 
^hndncal  surface,  C.  In  actual  operation,  the  hole, 
B,  IS  ground  to  size  first,  and  the  work  is  then  placed 


GBINDBe  FIXf  UllS 


24§ 


m.  110.  WEsmjm  wm  internaij  o^indino  a  ball-beabin(}  caoe 

on  an  expanding  arbor  and  the  surface,  C,  is  ground 
in  the  correct  relation  to  the  hole,  B.  The  fixture 
used  for  grinding  the  hole,  B,  was  originally  made 
up  for  boring  and  turning,  but  was  later  adapted  to 
the  present  use.  Since  the  fixture  was  made  up  for 
a  heavier  variety  of  work  than  a  grinding  operation, 
the  clamps  shown  at  D  are  much  more  suited  to  a 
turning  operation  than  they  are  to  a  grinding  fix- 
ture; so,  also,  the  driving  pin  shown  at  E  would 
usually  be  considered  unnecessary  if  the  fixture  were 
made  up  for  a  grinding  fixture.  This  example  is 
given  principally  to  sbow  how  a  fixture  made  up 


TOOLS  AND  PATTEkNS 


for  turning  and  boring  can  be  adapted  to  a  grinding 
operation  if  necessary. 

If  this  fixture  had  been  designed  originally  for 
grinding,  spring  clamps  conld  have  been  used  in 
place  of  the  straps  shown  at  D,  and  the  driving  pin, 
E,  could  have  been  omitted.  In  addition  to  this,  the 
entire  fixture  coxdd  have  been  made  much  lighter 
in  its  general  construction,  and  would  have  answered 
the  purpose  fully  as  well.  The  adapting  plate,  F, 
was  made  up  in  this  particular  case  to  fit  the  spindle 
of  the  grinding  machine,  and  the  faceplate,  G,  was 
fitted  to  it  as  indicated.  A  special  form  of  chuck, 
having  a  series  of  jaws  and  operated  by  means  of  a 
draw-in  mechanism  through  the  spindle,  can  often 
be  used  for  work  similar  to  that  shown.  An  example 
of  this  type  of  holding  device  is  described  later  in 
this  chapter. 

Qriiidiiig  TutmB  for  Uniyersal  Joint  Member.— 

A  good  example  of -a  fixture  used  for  grinding  a 
tapered  hole  is  shown  in  Figure  111.  This  fixture 
has  a  number  of  conmiendable  points,  one  of  which 
is  that  it  may  be  adjusted  to  take  care  of  slip! 
variations  caused  by  distortion  in  hardening  the  work 
previous  to  the  grinding -operation. 

The  method  of  setting  up  the  work  in  this  instance 
is  rather  out  of  the  ordinary.  In  the  first  place  tlie 
work  requires  that  the  tapered  hole,  A,  must  be 
ground  concentric  with  the  hole,  B,  and  at  right 
angles  to  the  cross-hole,  C.  For  this  reason  the  work 
is  located  on  a  sUding  rod,  D,  which  has  a  bearing 
in  the  spindle  at  E,  so  as  to  run  concentric  with  the 
spindle.  A  shoulder,  B,  on  the  rod,  D,  locates  the 


GRINDING  FIXTURES 


247 


no.  111.    GRINDING  FIXTURE  FOR  A  UNIVERSAL  JOINT  MEMBER 


work  in  a  central  position.  After  it  is  so  located, 
the  hardened  and  ground  bar,  F,  is  passed  through 
the  cross-hole,  C,  after  which  the  washer,  G,  is 
slipped  into  place  and  the  draw-hack  rod,  D,  oper- 
ated from  the  rear  end  of  the  spindle,  pulls  back 
the  work  until  the  bar,  F,  seats  itself  in  the  two 
V-blocks,  H,  on  the  fixture.  (The  small  detail  shown 
below  the  illustration  indicates  the  method  by  which 
the  bar,  F,  is  located  in  the  V-block.) 

A  refinement  provided  on  this  fixture  is  the 
knurled  button,  L,  whereby  variations  in  the  work 
can  be  compensated.  There  are  three  of  these  but- 
tons located  120  degrees  apart  on  the  face  of  the 
fixture,  but  only  one  of  them  is  shown  in  the  illus- 


248 


TOOLS  AND  PATTBKNS 


tration.   An  indicator  may  be  used  in  the  hole,  A 
to  approxunate  its  truth  before  the  grinding  take.' 
place  aad  these  buttons  can  then  be  set  up  to  £l 
the  hole  in  the  desired  position.    After  the 
ha^  been  properly  set,  it  is  grotmd  by  the  sma 
gnnding  wheel  shown  at  M,  using  an  internal  S 
mg  attachment  or  an  internal  grinding  machine  for 
tihe  work.   Applications  of  the  principle  shown  nm 
be  used  for  other  cases  of  similai-  character 

t^af^  ^'^^  Spur  Gear»._After 

gear  has  been  n,achined  and  the  teeth  have 
been  cut  It  IS  frequently  put  through  a  process  of 
pa^k-hardening  or  treating  in  some  way  to  prodnc 

metal  so^that  rt  will  withstand  abuse  without  frac 

to  C"^  ^"'^^^^S  there  is 

work        «  I  ^        «hape  of  the 

mptS^  J  *°  hole,  a 

method  of  compensating  for  any  error  from  the 
hardemng  process  is  highly  desirable. 
The  work,  A,  shown  in  Fieurp  1 1 9      „  „ 

t:";irth^;  rT'i-'"^^^^^^^^ 

teeth  around  the  periphery  of  the  gear.   To  as- 
«mre  this  result  the  method  of  lopntino.  +t„ 
liA  Hato,^-«»^    ui.  locating  the  gear  must 

be  J^™™ed  either  by  the  pitch  line  of  the  teeth 
or  else  from  the  bottom  of  the  t«»tl.  *i. 
\itiU  nt^>i;i.«.vj  4.1.  X  wetn,  for  there  is 

^^Li  J^^r^         "T"  ^^^«ge  their 

tln^?i^  the  eeBter  of  the  gear  because  of  distor- 

tCf^^i^"   ""'^^^         ^  ^^^^         the  bottom  of 
the  tooth    ufiuaUy  selected  as  the  locating  pXT 


GRINDING  FIXTURES 


249 


HG.  112.    SECTION  AND  PLAN  OF  AN  ABAPTABU:  FIXT0BE  FOB 


OBINDINO  SPUR  GEARS 

The  fixture  shown  in  the  illustration  consists  of  a 
nose  piece,  C,  mounted  on  the  spindle,  D,  and  pro- 
vided with  a  tapered  portion,  E,  as  indicated.  The 
gear  is  held  and  located  by  a  series  of  blocks,  F, 
each  of  which  has  a  point,  G,  so  designed  that  it 
will  strike  the  bottom  of  six  teeth,  as  indicated. 
These  six  blocks  are  radially  located  in  a  split  mem- 
ber, H,  by  means  of  the  clamps  shown  at  K.  This 
split  member,  H,  is  slotted  in  six  places  in  order 
to  allow  it  to  contract  as  it  is  pulled  back  into  the 
tapered  portion,  E,  by  means  of  an  internal  mech- 
anism running  through  the  spindle  as  indicated  at 
L  A  spider-shaped  piece,  M,  is  set  into  the  base 
piece,  C,  between  the  slots,  N,  which  provide  for  ex- 
pansion and  contraction  of  the  piece,  H.  This  spider 
is  provided  in  order  to  give  an  endwise  location  to 
the  work. 

It  will  be  seen  that  as  the  work  is  placed  in  the 
chuck,  the  points,  6,  are  drawn  in  radially  until  they 
center  the  work  from  the  bottom  of  the  six  teeth 
as  indicated.   This  mechanism  may  be  applied  to  a 


250  TOOLS  AND  PATTERNS 


FIG.  113.    ADJUSTABLE  FIXTTJBE  FOB  QBINDINO  A  BEVEL  PINION 


gear  having  an  odd  number  of  teeth  by  making  up 
the  blocks  to  suit  the  conditions. 
Adjustable  Fixture  for  Grinding  a  Bevel  Pinion.- 

A  bevel  gear  that  has  been  hardened  is  subject  to 
the  same  changes  as  those  that  may  be  produced  in 
a  spur  gear.  It  must,  therefore,  be  set  up  for  the 
grinding  operations  in  such  a  way  as  to  compensate 
for  any  errors  caused  by  the  hardening  process.  In 
this  case,  the  pitch  line  of  the  gear  is  generally  used 
as  a  locating  point.  Taking  the  example  shown  in 
Figure  113:  the  work,  A,  is  to  be  ground  in  the 
tapered  hole,  B,  which  must  be  concentric  with  the 
teeth  cut  on  the  outside  of  the  gear. 

A  different  type  of  fixture  is  provided  for  this 
class  of  work.  A  special  nose  piece,  C,  is  screwed 
to  the  end  of  the  spindle  in  the  usual  manner,  and 
is  provided  with  four  holes,  D,  in  which  are  inserted 
the  round  wires,  E,  which  pass  through  rollers,  F, 


QEINDING  FIXTURES 


251 


and  rest  against  a  hardened  ring,  G,  located  in  the 
nose  piece  and  having  a  suitable  taper  so  that  the 
center  line  of  the  roller  will  adapt  itself  to  the  pitch 
line  of  the  gear. 

An  enlarged  view  of  one  of  these  rollers  is  shown 
m  section  at  the  lower  part  of  the  illustration.  It 
will  be  seen  that  the  center  hole  through  the  rollers 
is  tapered  for  clearance  only,  so  that  a  floating  action 
is  permitted,  allowing  them  to  adapt  themselves  to 
the  gear.  Provision  is  made  for  supporting  the  wire 
at  the  inner  end  of  the  chuck  by  means  of  the  ring, 
H,  and  suitable  holes  are  drilled  to  receive  the  ends 
of  the  wire.  When  setting  up  the  work.  A,  it  is 
placed  in  the  chuck,  and  the  various  rolls  find  their 
location  on  the  fixed  line  of  the  gear.  The  spring 
clamps,  K,  are  then  swung  around  into  position  to 
hold  the  gear  in  this  location.  The  work  is  then 
ready  for  grinding. 

This  type  of  fixture  also  can  be  adapted  to  bevel 
pinions  of  odd  or  even  teeth  by  slight  changes  in 
the  roll  location  and  by  suitable  rings  of  the  correct 
angle,  as  shown  at  G. 

Orinding  Fixture  for  a  Large  Bevel  Spring  Gear. 

The  bevel  ring  gear  used  in  the  rear  axle  of  an  auto- 
mobile is  likely  to  change  somewhat  during  the  hard- 
ening process;  and  it  is  essential,  therefore,  to  grind 
it  after  hardening  in  such  a  way  that  the  teeth  and 
the  center  hole  will  be  in  correct  relation  to  each 
other.  For  this  purpose  a  fixture  can  be  made  up 
for  grinding  similar  to  that  shown  in  Figure  114. 

In  this  case,  the  work  is  located  by  means  of  a 
master  gear,  shown  at  A  in  the  figure.   This  master 


252 


TOOLS  AND  PATTERNS 


FIG.  114.    GRINDING  FIXTURE  FOR  THE  LARGE  BEVEL  RING  GEAR  IN 
THE  REAR  AXLE  OF  AN  AUTOMOBILE 


gear  is  an  exact  duplicate  of  the  gear  which  is  to 
be  ground,  and  is  fastened  to  the  faceplate  shown 
at  B,  so  that  the  pitch  line  of  the  master  gear  is 
ooncentrie  with  the  center  of  the  spindle.  In  opera- 
tion, the  work,  C,  is  placed  in  position  against  the 
face  of  the  master  gear  and  with  the  teeth  between 
those  of  the  master  gear.  As  each  of  the  gears  is 
beireled,  the  bevels  act  in  such  a  way  as  to  center 
the  gear  in  the  correct  position.  After  the  location 
has  been  assured,  the  spring  clamps,  D,  are  adjusted 
to  hold  the  work  properly.  As  little  pressnre  is  re- 
quired to  hold  a  piece  of  work  of  this  kind,  these 
clamps  answer  the  purpose  very  well  and  can  be 
quickly  adjusted  to  position.  The  principle  shown 
here  can  be  adapted  to  any  work  of  this  character 
and  the  work  obtained  by  its  use  gives  excelleat 
results. 


CHAPTER  XVII 


OPEN  DRILL  JIGS 

Functions  and  Operation. — Strictly  speaking,  a 
drill  jig  is  a  device  by  means  of  which  a  piece  of 
work  may  be  properly  located  and  clamped  in  order 
that  a  series  of  holes  may  be  drilled  in  the  work  at 
certain  fixed  locations.  It  will  be  seen,  then,  that  any 
number  of  pieces  of  similar  shape  and  form  can  be 
placed  one  after  the  other  in  a  drill  jig  and  all  the 
pieces  will  be  made  in  snch  a  way  as  to  be  inter- 
changeable. Not  only  is  a  drill  jig  provided  with 
the  proper  methods  of  clamping  and  holding  the 
work,  but  there  are  also  a  number  of  bushings,  cor- 
responding to  the  number  of  holes  in  the  piece, 
located  in  the  jig  in  such  a  way  that  the  drills  used 
in  the  manufacture  will  pass  through  these  bush- 
ings and  be  guided  thereby.  The  bushings  are  made 
of  hardened  tool  steel,  and  are  located  very  care- 
fully by  a  toolmaker  in  their  oorreet  positions  to 
produce  the  holes  desired. 

Natumlly,  the  shape  of  the  work  to  be  held  exer- 
eises  a  powerful  influence  on  the  form  of  jig  to  be 
designed  for  the  work.  It  is  evident  that  a  jig  for  a 
simple  piece  of  work  which  can  be  held  easily  by  a 
couple  of  simple  clamps,  m  much  easier  to  design 
iuaii  one  which  is  of  such  shape  as  to  require  very 

258 


254 


TOOLS  AND  PATTERNS 


special  methods  of  locating  and  clamping.  In  order 
to  illustrate  the  functions  of  a  drill  jig,  let  us  suppos 
that  a  hole  is  to  be  drilled  in  each  end  of  a  simple 
lever,  and  that  the  work  is  to  be  done  in  a  drill  jig. 
Let  us  further  suppose  that  the  workman  has  a  drill 
jig  before  him  on  the  table  of  a  drill  press,  and  that 
he  is  ready  to  do  the  work.  He  takes  the  work  in 
one  hand,  then,  and  places  it  in  position  in  the  drill 
jig,  clamping  the  work  securely  by  means  of  the 
elamps  provided  in  the  jig.  After  this  he  pulls  the 
drill  jig  under  the  drilling-machine  spindle,  or 
spindles,  and  proceeds  to  feed  the  drill  down  through 
the  bushings  provided  for  it  in  the  jig.  After  the 
drill  has  been  pressed  through  the  work  to  the  proper 
distance,  the  workman  raises  the  spindle,  removes 
the  jig  to  a  convenient  position  on  the  table,  and 
releases  the  clamps  which  hold  the  work  in  place. 
This  allows  the  piece  to  be  taken  out  of  the  jig  and 
replaced  by  another  one,  and  the  process  is  repeated. 

When  drill  jigs  are  to  be  made  for  large  work,  or 
when  a  number  of  holes  are  to  be  drilled  at  different 
angles  or  from  different  sides,  it  is  necessary  to 
make  up  a  drill  jig  of  more  elaborate  form.  If  the 
work  is  very  large  and  heavy,  trunnion  jigs  are 
frequently  employed.  Jigs  of  this  character  are  so 
made  that  the  work  is  placed  in  jKMsition,  clamped, 
and  the  entire  jig  is  revolved  on  a  bearing  at  each 
end,  this  bearing  being  the  term  from  which  the 
word  trunnion  is  derived.  A  trunnion  jig  is  mounted 
.  on  a  pedestal,  or  base  of  some  kind,  in  such  a  way 
that  it  can  be  -swung  into  the  correct  position  for 
drilling.   It  is  also  provided  with  suitable  indexing 


OPEN  DRILL  JIGS  , 


255 


mechanisms,  in  order  to  locate  the  jig  properly  at 
the  various  angles  in  which  it  is  to  be  drilled.  Some- 
times trunnion  jigs  are  mounted  on  a  sort  of  carriage 
which  can  be  rolled  from  one  drill-press  table  to 
another,  in  order  to  take  advantage  of  special  group- 
ing of  the  spindle. 

In  regard  to  the  grouping  of  spindles,  it  must  be 
remembered  that  many  drill  jigs  are  used  on  mul- 
tiple-spindle drilling  machines.  A  number  of  drilling 
machines  of  this  character  can  be  arranged  one  after 
the  other  and  connected  by  means  of  a  track  or 
miniature  railroad  on  which  a  trunnion  jig,  suitably 
mounted  on  a  carriage  with  wheels  which  fit  the 
rails  of  the  railroad,  can  be  rolled  from  one  machine 
to  the  other  and  indexed,  as  previously  mentioned. 
An  arrangement  of  this  sort  can  be  used  for  such 
work  as  an  automobile  cylinder  or  crank-case,  or  a 
machine-tool  gear  box,  or  some  other  piece  of  work 
that  requires  a  number  of  holes  to  be  drilled  in  it 
from  different  sides.  The  advantage  of  such  a  jig 
is  that  the  work  is  once  clamped  in  position  and  is 
not  released  until  all  of  the  holes  have  been  drilled. 
In  this  way,  the  jig  makes  it  possible  to  obtain  a 
number  of  pieces  of  work,  all  of  which  are  drilled 
in  exactly  the  same  relation  to  each  other.  Drill 
jigs  can  be  designed  so  that  their  work  can  be  done 
on  any  type  of  drill  press,  from  a  slngle^pindle  ma- 
chine to  one  of  the  multiple  type. 

A  number  of  points  must  be  considered  in  the  de- 
sign of  a  drill  jig:  the  method  of  locating  the  work 
in  position;  the  method  of  clamping  it  so  that  it  will 
l>e  firmly  held  against  the  pressure  of  the  drill  and 


256 


TOOLS  AND  PATTERNS 


at  the  same  time  will  not  be  distorted  by  the  pressure 
of  the  clamp;  clearance  around  the  work;  provision 
for  chips;  easy  aoeessibility  for  cleaning  so  that  no 
variation  in  the  work  can  be  cansed  by  chips  or  their 
accumulation  on  the  locating  point;  and  finally  a 
method  of  clamping  which  will  be  both  rapid  and 
positive  in  aetion. 

When  a  series  of  jigs  is  to  be  made,  these  points 
must  all  be  taken  into  consideration  if  the  jigging 
process  is  to  give  correct  results.  Any  incorrect 
method  of  locating,  or  any  method  of  clamping  which 
tends  to  distort  the  work,  may  cause  a  great  deal 
of  trouble  and  expense;  for  even  with  work  requiring 
great  accuracy  it  i»  entirely  possible  to  drill  a  series 
of  holes  in  sneh  a  way  that  they  will  not  coincide 
with  other  holes  to  which  the  work  is  to  be  fitted. 
Again,  if  the  work  is  strained  by  the  method  of 
clamping,  the  hole  will  not  line  np  properly  with 
the  other  work  and  a  great  deal  of  unnecessary  fit- 
ting nmst  be  done  when  the  parts  are  assembled. 

In  taking  up  the  more  common  types  of  drill  jigs, 
let  us  consider  that  the  two  most  general  types  are 
the  open  and  the  closed  jigs.  An  open  jig  is  one 
in  which  the  work  is  held  in  such  a  way  that  it  is 
not  enclosed.  A  closed  jig  is  one  of  the  box  type, 
where  the  work  is  placed  in  a  sort  of  box  or  frame 
and  is  usually  drilled  from  several  sides  in  the  same 
setting. 

A  Simple  Plate  Jig.— The  work  shown  at  A,  Figure 
115,  is  a  cast-iron  flange  which  is  to  be  drilled  with 
six  holes,  B,  located  in  a  circle  around  one  face  of 
the  flange.    This  is  an  extremely  simple  piece  for 


257 


Vm.  115.    SIMPIiE  VhkTR  JIG 

which  to  make  a  jig  and,  therefore,  it  is  used  as  an 
example  to  show  what  simple  forms  may  be  used  for 
jigging  purposes. 

In  this  case,  the  work  has  been  previously  bored 
and  reamed,  so  that  the  jig  plate,  C,  can  be  located 
directly  on  the  upper  flange  by  means  of  a  plug,  D, 
which  enters  the  roll.  The  jig  plate  is  provided  with 
a  series  of  bushings,  E,  so  located  in  the  plate  as  to 
give  the  resired  location  to  the  hole.  For  a  piece 
of  work  of  this  kind  no  clamping  device  is  necessary, 
as  the  work  is  usually  done  on  a  multiple-spindle 
drill  press,  each  spindle  of  which  contains  a  drill  of 
the  proper  size  for  the  work.   These  drill  spindles 


TOOLS  AND  PATTERNS 


are  adjustable,  so  that  they  can  readily  be  made  to 
correspond  to  the  holes  in  the  jig.  In  operation,  a 
jig  of  this  kind  is  simply  dropped  on  the  work  which 
is  located  on  the  drill  press  table,  and  immediately 
thereafter  the  spindles  of  the  drill  press  are  brought 
down  until  they  enter  the  bushings;  after  this  the 
feed  is  started  and  the  work  is  completed  without 
any  clamping  device  being  necessary.  The  pressure 
of  the  drill  is  sufficient  to  hold  the  work  in  position, 
and  after  the  holes  have  once  been  started  there  is 
no  necessity  for  any  method  of  clamping  to  keep  the 
jig  properly  located.  Jigs  of  this  kind  are  suited 
to  many  kinds  of  work  that  have  been  previously 
machined,  as  indicated,  and  also  to  work  that  has  a 
finished  face  on  which  to  rest  it  while  the  drilling 
is  taking  place. 

Plate  Jig  with  Supplementary  Supporting  Sing.— 
Another  type  of  plate  jig,  more  suited  to  work  that 
would  be  unstable  without  support  while  being 
drilled,  is  shown  in  Figure  116.  This  piece  of  work 
has  been  previously  finished  on  both  sides  of  the 
fiange,  B,  and  ako  on  the  outside  of  the  hub,  C.  It 
will  be-  seen,  however,  that  the  piece  could  not  be 
drilled  very  well  without  some  sort  of  support,  be- 
cause the  radius  of  the  hole,  E,  is  out  beyond  the 
base  of  the  hub,  A,  and  if  the  work  were  to  be  drilled 
without  any.  support,  it  would  be  likely  to  tip  one 
way  or  the  other  unless  all  the  drills  were  exactly 
of  the  same  length.  In  order  to  oi||||||||e  any 
tendency  of  this  sort,  a  cast-iron  ring,  I*,  i«  made  to 
act  as  a  support  for  the  work.  This  ring  is  made  of 
sufiScient  diameter  and  stability  to  allow  the  work  to 


OPEN  DRILL  JIGS 


FIG.  116.    PLATE  JIG  WITH  SUPPLEMENTARY  PLATE 


rest  on  the  flange  at  B  and  be  supported  thereby. 
The  drill-jig  plate,  D,  in  this  case,  is  made  so  that 
it  will  slip  over  the  hub,  C,  and  is  provided  with  a 
series  of  bushings,  B,  arranged  in  circular  form  to 
give  the  correct  spacing  of  the  holes. 

In  some  cases,  the  holes  to  be  drilled  may  be  of 
several  diameters,  and  drills  of  corresponding  diam- 
eter are  used.  However,  when  an  occasion  of  this  kind 
arises,  some  method  of  location  must  be  provided,  both 
for  the  work  and  for  the  drill-jig  plate  in  order  that  the 
correct  bushings  may  be  located  properly  under  the 
corresponding  drill. 

This  kind  of  jig  is  usually  used  on  a  multiple- 
spindle  drill  press,  with  the  spindles  grouped  to  the 
correct  radial  setting.  Adaptations  of  the  two  forms 
0^  jigs  just  mentioned.  Figures  115  and  116,  may  be 
made  to  cover  a  variety  of  cases.    Such  jigs  are 


260 


TOOLS  ANB  PATTIENS 


f  i 

1 

H 


;  ■  '  -/jjT*  I  I 

i  !g!  '"^^tt^J^r^r  ~  ill 

rr   !•  !l 


Kt 


'r 
!« 


•I 


c... 


TO.  117.    mm,  JIG  FOB  AN  OIL-PUMP  COVER 

cheap  in  their  eomtruction  and  answer  the  purposes 
forwhich  they  are  intended  very  well  indeed. 

DnH  Jig  for  sm  Oil-Pump  Cover.— The  work  shown 
at  A,  Figure  117,  is  an  aluininnm  oil-pnmp  cover 
which  has  been  previonsly  faced  on  the  surface,  B, 
but  has  not  been  turned.  Due  to  the  fact  that  only 
one  surface  on  this  piece  has  been  machined,  it  is 
necessary  to  locate  from  this  snrface  for  the  opera- 


OPEN  DRILL  JIGS 


261 


tion  of  drilling  the  six  holes  shown  at  C.  In  order 
properly  to  accomplish  a  correct  location  for  this 
Avork,  the  vee  principle  is  tised. 

In  the  example  shown  in  Figure  117,  the  two  pins 
at  D  are  used  as  locaters  of  this  kind.  The  work  is 
forced  against  or  between  these  pins  by  means  of  the 
thumb  screw  shown  at  E,  and  is  further  located  by 
means  of  the  stop-screw,  F,  against  which  the  boss 
is  clamped  by  means  of  another  screw,  G.  The 
clamps,  H,  are  then  tightened,  thus  holding  the  work 
firmly  against  the  face  of  the  fixture  and  down  on 
the  surface,  B.  With  the  work  in  this  position,  the 
entire  jig  is  turned  over  onto  the  legs,  K,  on  which 
it  rests  while  the  drilling  operation  takes  place. 
These  legs  are  a  part  of  the  base  casting  of  ike  jig, 
and  are  surfaced  in  such  a  way  as  to  provide  an  ample 
means  of  support  which  is,  at  the  same  time,  parallel 
with  the  surface,  B.  Bushings  are  provided  for  the 
holes  at  C,  as  in  the  former  instances  described.  It 
will  be  seen  that  after  the  jig  has  been  turned  over, 
the  pressure  of  the  drills  comes  entirely  against  the 
clamps.  H.  These  clamps,  therefore,  must  be  suffi- 
ciently strong  and  heavy  to  withstand  the  pressure. 

Jigs  of  this  kind  are  very  useful  for  many  kinds 
of  semi-cylindrical  work  where  there  is  a  single  fin- 
ished surface  and  a  series  of  holes  arranged  more  or 
less  centrally  about  the  center  of  the  piece.  Applica- 
tions of  the  principles  shown  in  this  jig  can  be  made 
to  a  great  variety  of  work. 

Open  Jif  for  a  Lever.— Jigs  designed  for  drilling 
holes  in  levers  are  of  two  kinds:  those  which  locate 
from  the  work  in  its  unfinished  state  or  which  locate 


262 


TOOIiS  Am  PATTIBNS 


on  bosses  at  either  end  of  the  lever;  and  those  which 
locate  for  a  single  drilling  operation  of  one  end-hole 
from  a  previously  bored  or  reamed  hole  in  the  other 
end.  Both  of  these  jigs  are  in  common  use  and  will, 
therefore,  be  described  separately.  The  type  men- 
tioned first  is  shown  in  Fignre  118.  In  this  case  the 
lever,  A,  has  been  finished  by  straddle  milling  the 
side  of  the  bosses  at  each  end.  The  jig  shown  is  for  the 
purpose  of  drilling  the  two  holes,  B,  at  each  end  of 
the  lever. 

The  method  of  locating  used  for  this  piece  is  a 
vee  block,  C,  in  which  the  boss  at  one  end  of  the 


OPEN  DEUili  JIGS 


263 


lever  rests.   The  other  end  of  the  lever  is  located 
and  clamped  simultaneously  by  means  of  the  sliding 
yee-block,  D.   This  vee-block  is  chased  up  into  posi- 
tion by  means  of  the  thumb  screw,  E,  located  in  a 
swinging  latch,  F,  between  the  bosses,  G,  through 
>vhich  a  pin  is  passed.    An  additional  support  is 
given  the  latch  at  the  other  end  on  the  lug,  H.  After 
the  work  has  been  located  as  mentioned,  it  is  clamped 
firmly  by  means  of  the  wide  clamp,  L,  which  is 
slotted  so  that  it  can  be  pushed  back  out  of  the  way 
to  allow  the  piece  to  be  placed  in  position.  When 
the  work  has  been  clamped  as  indicated,  the  entire 
jig  is  turned  over,  so  that  it  rests  upon  the  two  feet, 
K,  after  which  the  holes  are  drilled  through  the  bush- 
ings indicated. 

This  type  of  jig  is  in  common  use,  with  certain 
modifications  in  regard  to  clamping  and  locating  in 
accordance  with  the  nature  of  the  piece  to  be  drilled. 
It  is  comparatively  inexpensive  and  gives  excellent 
results. 

Ofm  Jig  for  a  Lever  with  Stud  Locater.— The 

lever,  A,  Figure  119,  is  of  similar  shape  to  that  shown 
in  Figure  118,  but  it  is  of  larger  size,  and  the  end,  B, 
has  been  bored  and  reamed  in  a  previous  operation. 
It  is,  therefore,  necessary  to  locate  from  this  hole  to 
drill  the  small  end,  C.  A  stud,  D,  is  placed  in  the 
jig  body,  and  the  work  is  placed  over  it  as  indicated. 
The  small  end,  C,  is  located  by  means  of  a  sliding 
vee-block,  E,  which  is  forced  up  against  the  boss  by 
means  of  a  thumb  screw,  F.  The  work  is  keld  in 
position  and  supported  against  the  pressure  of  the 
cut  by  means  of  the  clamp  shown  at  G.  As  in  the 


TOOLS  AND  PATTERNS 


FIG.  119.    (MPEN  JIG  WITH  STUD  liOCATEB 


former  case,  after  the  work  has  been  located  in  the 
jig  it  is  turned  over,  so  that  it  rests  upon  the  feet,  K, 
in  wMeli  position  it  is  drilled.  Jigs  of  this  kind  are 
nearly  as  common  as  that  shown  in  Figure  118,  and 
their  application  to  many  shapes  of  levers  will  be 
apparent. 

Open  Jig  for  a  Small  Bnuskit— The  work  shown 
at  A,  Mgnre  120,  is  a  small  bracket  which  is  to  be 
drilled  at  B,  C,  and  D.  The  holes,  B  and  C,  are  in 
one  plane,  and  the  hole,  D,  is  in  another.  Therefore, 
the  jig  mnst  be  so  made  that  it  can  be  tnmed  on  one 
side  for  the  latter  hole  and  on  another  side  for  the 
holes  at  B  and  C.  The  use  of  a  vee-block  is  seen  in 
this  fixture  at  E,  and  the  rounded  angular  end  of  the 


OPEN  DRILL  JIGS 


265 


work  rests  in  this  block  as  it  is  forced  there  by  means 
of  the  set-screw  shown  at  P.  It  will  be  seen  that  this 
set-screw  is  placed  at  an  angle  and  also  that  the  vee- 
block,  E,  has  an  angular  face.  The  purpose  of  this 
is  to  make  sure  that  the  work  will  be  held  down 
firmly  and  located  correctly.  The  work  rests  on  the 
flat  milled  surface,  G,  and  suitable  bushings  are  pro- 
vided for  the  various  holes.  An  additional  clamp  is 
provided  at  H  in  order  to  make  the  clamping  action 
more  positive.  Legs  are  provided  on  the  side  of  the 
jig  at  K  and  also  at  L,  so  that  the  work  can  be 


26G 


TOOLS  AND  FATTEBNS 


WG.  121.    SET-ON  JIO  Vm  A  TRANSMISSI0N-GA8E  COVER 


drilled  in  the  correct  positions.  Additional  legs  are 
also  made  at  M  for  purposes  of  setting  up  the  work. 

Set-on  Jig  for  a  Transmission-case  Cover.— When 
a  large  piece  of  work  is  to  be  handled  and  a  small 
portion  of  it  only  is  to  be  drilled,  a  set-on  Jig  is  ad- 
vantageous. In  the  design  of  a  jig  of  this  kind  it  is 
always  necessary  to  consider  the  bearing  which  the 
work  itself  will  have  on  the  table  of  the  drill  press, 
in  order  that  the  pressure  of  the  drills  as  they  enter 
the  work  may  not  be  in  snch  a  position  as  to  cause 
the  work  to  topple  over  or  tip  on  one  side. 

An  example  of  this  kind  is  shown  in  Figure  121. 
In  this  case,  the  work,  A,  has  been  previously  fin- 
ished by  milling  along  the  surface,  B,  and  also  on 
the  face,  C.   At  C,  four  holes  are  to  be  drilled  as 


OPBN  msMMi  Mm 


267 


shown  at  E  in  the  upper  view.  The  surface,  B,  is 
sufficiently  solid  to  rest  on  the  drill-press  table  with- 
out difficulty. 

The  drill  jig  is  made  of  cast  iron  and  consists  of  a 
pipe,  D,  with  lugs  at  each  end  through  which  the 
set-screws,  F,  are  passed  to  act  as  an  end-stop  for 
the  jig  when  it  is  placed  in  position  on  the  work. 
Another  stop-pin  is  placed  on  the  other  side  of  the 
jig  plate,  as  shown  at  H  in  the  upper  view,  and  in 
placing  the  jig  plate  on  the  work  this  pin  is  brought 
up  against  the  side  of  the  work  before  the  set-screw, 
shown  at  G,  is  tightened.  As  this  set-screw  is  tight- 
ened it  will  be  seen  that  the  entire  jig  is  clamped  in 
place  on  the  top  of  the  work.  The  jig  plate  is  pro- 
vided with  a  series  of  bushings,  E,  through  which 
the  drills  arc  passed  as  the  four  holes  are  drilled. 
This  is  a  very  simple  type  of  jig,  but  application  of 
the  principle  shown  can  be  used  on  many  other  cases 
for  work  of  similar  kind. 

SeUm  Jig  tmt  a  Gas-Control  Plale^— Set-on  jigs  are 
sometimes  used  for  small  as  well  as  for  large  pieces 
when  the  size  of  the  work  is  such  that  it  can  be  used 
to  advantage.  In  designing  a  jig  of  this  kind  care 
must  be  exercised  to  see  that  there  is  sufficient  stabil- 
ity to  the  work  itself  to  permit  placing  and  support- 
ing the  jig  upon  it.  Figure  122  is  a  very  good  ex- 
ample of  a  piece  of  work  which  can  be  drilled  with 
this  type  of  mi^n  jig.  The  gas-control  plate,  A, 
in  this  case,  has  been  finished  in  a  previous  opera- 
tion, so  that  the  surface,  B,  is  perfectly  plane  and 
can  therefore  be  used  for  setting  up  the  work.  The 
jig  is  placed  on  the  top  of  the  piece  as  indicated  in 


TOOLS  AND  FATTliBNS 


f 


fiCL  122.  SKMXK  m  wm  mMJu  vmm  or  work 

the  illustration,  and  the  two  pins,  shown  at  C,  in 
reality  form  a  sort  of  Y  against  which  the  work  is 
forced  by  means  of  the  set-screw  at  the  other  end 
of  the  jig.  This  set-screw,  D,  forces  up  the  work 
and  locates  it  at  the  same  time  by  means  of  the  vee- 
blocki  E.  A  series  of  bushings  are  arranged  to  drill 
the  holeSy  F  and  Q,  in  the  top  view. 

It  will  be  seen  that  when  this  jig  is  to  be  used,  it 
is  only  necessary  to  place  it  in  position  on  top  of 
the  work  while  the  work  is  resting  on  the  drill  press 
table  and  then  to  tighten  the  thnmb-screw,  D.  After 
this  has  been  done  the  jig  can  be  readily  moved 
under  the  spindles  of  the  drill  press,  in  which  posi- 
tion the  work  can  be  drilled  without  difficulty. 

The  number  of  other  jigs  which  could  be  classed 
under  the  heading  of  open  jigs,  is  so  great  that  it  is 
out  of  the  question  to  enumerate  the  different  types 


OPEN  DRILL  JIGS 


269 


in  a  book  of  this  kind.  My  effort,  therefore,  has 
been  to  show  new  forms  of  open  jig,  in  order  that 
the  discriminating  reader  may  be  able  to  form  an 
idea  of  the  various  types  and  their  application  to 
work  of  ordinary  nature.  Speaking  broadly,  an  open 
jig  can  be  made  for  almost  any  piece  of  work  when 
holes  are  to  be  drilled  from  not  more  than  three 
directions.  As  the  usual  thing,  however,  open  jigs 
are  designed  for  pieces  that  are  to  be  drilled  in  one 
or  two  directions  only 


CHAPTER  XVni 
ViAjiSMiD  Jllio 

Bushing  for  an  Oil-Pump  Shaft— In  the  previous 
efaapter  a  few  varieties  of  open  jigs  were  described, 
but  by  no  means  all  types  were  mentioned.  In  this 
chapter,  also,  it  will  be  impossible  to  enumerate  every 
type  of  closed  jigs,  and  yet  an  attempt  will  be  made 
to  cover  the  subject  in  a  broad  way,  so  that  the 
reader  will  be  able  to  get  a  good  idea  of  the  variety 
of  jigs. 

Beferring  to  Figure  123,  let  us  assume  that  the 
'  bushing  shown  at  A,  has  been  previously  bored  and 
reamed  in  the  hole,  C,  and  that  the  end,  B,  has  been 
faced.  Let  us  also  assume  that  the  outside  of  the  work 
has  been  completely  finished  to  the  form  shown,  and 
that  the  upper  end  has  also  been  faced.  The  work 
in  this  case  is  located  on  the  previously  finished  hole 
at  C  on  a  small  stud,  and  it  rests  against  the  sur- 
face, By  on  the  locating  stud.  While  in  this  position, 
it  is  clamped  by  means  of  the  sei^screw  shown  at  H. 
A  button  on  the  end  of  the  set-screw  bears  against 
the  end  of  the  piece. 

This  type  of  jig  is  arranged  in  such  a  way  that 
holes  can  be  drilled  in  the  work  at  two  different 
angles.  The  jig  is  turned  over  on  the  legs,  F,  while 
the  hole  located  by  the  bushing,  D,  is  drilled.  After 


CLOSED  JIGS 


271 


HG.  123.    BUSHING  FOR  AN  OILrPUMP  SHAFT 


this  is  done,  the  jig  is  turned  over  until  it  rests 
upon  the  legs,  K.  In  this  position,  the  drill  is  guided 
by  the  long  bushing  shown  at  G.  As  this  bushing 
is  so  very  long,  it  will  be  noticed  that  it  is  relieved 
to  a  size  a  little  larger  than  the  drill  for  a  good  pro- 
portion of  its  length. 

As  the  piece  of  work  shown  in  this  illustration  is 
cylindrical  in  its  general  form,  it  does  not  make  any 
difference  how  it  is  located  radially,  so  that  it  is 
only  necessary  to  slip  it  on  to  the  stud  and  tighten 
the  clamp  screw,  H,  before  starting  the  work.  A 
drill  jig  of  this  kind  can  be  used  for  many  kinds  of 
bushing  work  when  oil  holes  or  other  holes  of  sim- 
ilar kind  are  to  be  drilled.  It  forms  an  excellent 
example  of  a  simple  type  of  closed  jig.  Naturally, 
such  a  jig  is  used  on  a  drill  press,  either  with  a 
couple  of  spindles  in  which  the  different  size  drills 


m 


TOOLS  AND  PATTEINS 


are  plaeed  and  used  one  after  tlie  other,  or  else  a 
magic  elin<;k  or  its  equivalent  is  used  in  a  single 
spindle  machine,  and  sockets  for  each  of  the  drills 
are  provided  so  that  one  can  be  interchanged  for  the 
other  while  the  spindle  is  in  motion. 

Drill  Jig  for  a  Rod-Supporting  Bracket. — ^The  sup 
porting  bracket  for  a  rod  or  shaft,  shown  at  A,  Fig- 
ure 124,  has  been  previously  machined  in  a  hole 
which  extends  entirely  through  the  hub  indicated. 
At  the  time  when  the  hole  was  reamed,  the  end  of 
the  hub  was  also  faced.  In  a  subsequent  operation 
the  surface,  K,  was  milled  in  a  definite  relation  to  the 
reamed  hole.  In  the  operation  indicated  by  this  jig, 
the  work  to  be  done  is  the  drilling  of  the  two  holes, 
B,  and  also  the  one  from  the  opposite  side  as  indi- 
cated  at  0. 

As  the  hole,  F,  shown  entirely  through  the  hub 
has  been  previously  located  from  the  milled  surface, 
K,  when  it  was  machined,  it  is  obvious  that  a  loca- 
tion from  the  hole  and  the  miUed  surface  can  log- 
ically be  considered  as  the  correct  method  of  locat- 
ing for  the  present  operation.  In  order  to  support 
the  flanges  while  they  are  being  drilled,  the  two  set- 
screws,  E,  operated  by  the  workman's  fingers  are 
used.  These  set-screws  are  conical  on  the  end,  so 
that  they  set  up  a  slight  wedging  action  and  liokl 
the  work  securely.  The  piece  is  slipped  upon  a  locat- 
ing stud  in  the  large  hole,  and  after  it  has  been 
damped  against  the  opposite  end  of  the  hub  by 
means  of  the  C-washer  shown  at  F,  by  the  nut  indi- 
cated, the  set-screws,  E,  are  tightened  as  previously 
mentioned.  When  drilling  the  holes,  B,  the  jig  is  set 


CLOSED  JIGS 


273 


274 


TOOLS  AND  PATTERNS 


CLOSED  JIGS 


275 


up  upon  the  legs,  D.  When  the  hole,  C,  is  to  bo 
drilled,  the  entire  jig  is  turned  over  until  it  rests 
upan  the  legs  on  the  opposite  side.  This  completes 
the  drilling  operations  on  this  piece  of  work. 

This  is  one  of  the  simplest  types  of  jigs  which  can 
be  devised,  but  it  can  be  made  to  give^  excellent  re- 
sults in  ordinary  practice.  A  point  which  should  be 
mentioned  in  connection  with  a  jig  of  this  sort  is  that 
the  surface  on  the  jig  shown  at  K  should  be  so  milled 
in  relation  to  the  center  stud  on  which  the  work 
locates  that  there  will  be  a  slight  amount  of  clear- 
ance between  the  surface  of  the  piece  and  the  pad 
on  which  it  locates.  A  very  slight  amount  of  tipping 
may  be  caused  when  the  thumb-screws,  E,  are  tight- 
ened; but  in  actual  practice  this  amount  would  never 
be  sufficient  to  cause  any  trouble,  so  that  the  jig  can 
logically  be  considered  of  good  design.  In  addition, 
this  jig  is  easily  made  and  easily  cleaned,  and  chips 
are  not  likely  to  accumulate  on  the  locating  point, 
thereby  causing  errors  in  locating. 

Jig  for  Automobile  Hand  Lever. — Sometimes  an 
occasion  arises  to  make  a  jig  which  can  neither  be 
considered  an  open  jig  nor  yet  a  closed  jig.  Such  an 
example  is  indicated  in  Figure  125.  In  this  example, 
the  jig  is  a  kind  of  half  and  half  type,  and  is  not 
really  one  of  the  two  types,  but  is  midway  between 
them.  In  this  case,  the  work,  A,  is  a  hand  lever 
used  for  operating  a  pull  rod  or  latch  on  the  brake 
lever  of  an  automobile.  Previous  to  the  operation 
of  drilling,  the  work  has  been  milled  on  the  surface, 
F,  and  it  is  therefore  safe  to  use  this  surface  as  a 
locating  point  in  the  drilling  operation.    The  piece, 


FIG.  125.    JIG  FOR  AN  AUTOMOBILE  HAND  LEVER 

therefore,  is  laid  on  the  surface,  P,  in  the  jig  as  indi- 
cated, and  is  pushed  over  into  a  vee-block,  D,  by 
means  of  the  set-screw,  B.  This  set-screw  strikes 
against  a  corner  or  fillet  on  the  lever  in  such  a  way 
as  to  force  the  work  into  the  vee-block  and  at  the 
same  time  to  throw  it  over  until  it  strikes  the  end 
of  the  set-screw,  6.  It  will  be  seen  that  then  the 
set-screw,  G,  acts  as  one  side  of  a  vee,  the  other  side 
of  which  is  formed  by  the  thumb-screw,  E.   All  of 


TOOLS  AND  PATTERNS 


the  elamping  action  is  aeeomplislied  by  means  of  this 
one  screw  in  the  case  mentioned.  Little  difficulty  is 
experienced  in  setting  up  the  work  for  the  operation 
and  in  obtaining  a  correct  location. 

The  work  which  is  to  be  done  in  this  setting  of 
the  piece  is  the  drilling  of  the  two  holes,  B  and  C, 
and  the  entire  jig  is  set  up  on  the  leg  shown  at  E,  in 
the  lower  portion  of  the  illustration,  when  the  work  is 
done.  Bushings,  natnrally,  are  provided  at  B  and  C 
to  guide  the  drill  and  to  insure  correct  locations  for 
the  hole. 

Nearly  all  of  the  jigs  shown  so  far  in  these  two 
chapters  are  made  of  cast  iron,  as  this  material  lends 
itself  to  a  variety  of  forms  and  can  be  made  cheaply 
and  quickly.  But  the  same  types  of  jigs  can  be 
bnilt  up  from  steel  if  desired,  and  in  the  case  of  gun 
jigs  and  of  jigs  for  use  with  a  great  many  dull  pieces, 
the  steel  built-up  jig  is  to  be  preferred.  Its  cost, 
however,  is  prohibitive  in  anything  but  very  large 
production. 

Drill  Jig  for  a  Bearing  End*Cap.— When  a  piece 
of  work  has  been  previously  machined  and  it  is  nec- 
essary to  locate  it  for  a  drilling  operation  subsequent 
to  the  other  operations  on  the  work,  it  is  essential 
to  locate  the  piece  by  means  of  the  finished  surfaces. 
An  excellent  jig  for  a  piece  of  work  of  this  kind  is 
shown  in  Figure  126.  In  this  case  the  work.  A,  has 
been  previously  faced  at  B  and  has  been  recessed 
at  C.  It  is  necessary  then  to  locate  the  work  for 
the  drilling  of  the  four  holes  shown  at  F,  by  the 
previously  finished  surfaces.  The  method  of  doing 
this  is  to  set  the  work  upon  a  shallow  stud  or  plate, 


CLOSED  JIGS 


277 





 ]S^2^  _  ^  «  «.  J„ 





H' 


i  1    ;  •  1 

• 

:  n  :  1 

c 


no.  126.   DIOU.  JIG  IW  A  BEABINa  S£il)  GAP 

locating  it  by  means  of  the  recess  at  C,  and  clamping 
the  work  by  means  of  an  equalizing  collar,  H,  oper- 
ated by  the  thumb  screw,  K. 

In  placing  the  work  in  the  jig,  the  square  side  of 
the  piece  strikes  against  the  two  set  screws,  G,  thus 
giving  a  sqnaring-up  effect.  It  will  be  seen  that  the 


278  TOOLS  AND  PATTERNS 


action  of  the  clamp  collar,  H,  is  such  that  when  the 
thumb  screw,  K,  is  tightened,  the  entire  collar  rocks 
sufficiently  to  permit  an  equally  distributed  pressure 
on  the  work.  The  thumb  screw,  K,  is  mounted  in  a 
strap,  N,  which  extends  entirely  across  the  jig.  This 
strap  is  slotted  at  L  and  M  in  such  a  way  that  it 
can  be  quickly  removed  when  placing  a  piece  of 
work  in  the  jig  or  removing  one  from  it. 

In  operation  the  jig  is  set  up  on  the  four  legs 
shown  at  D,  and  the  work  is  slipped  into  position. 
After  this  is  done  the  strap  is  put  in  place  and  the 
thumb  screw,  K,  is  tightened.  The  entire  jig  is  then 
turned  over  until  it  rests  on  the  legs,  E.  Bushings 
are  provided  at  P  to  guide  the  drills  to  their  proper 
positions. 

This  type  of  jig  can  be  used  for  many  varieties 
of  work  of  a  similar  character,  the  only  variation 
nec^usary  is  in  the  manner  of  locating  the  piece  and 
in  little  details  of  clamping,  and  so  on.  The  type 
itself  is  a  common  one,  the  use  of  which  can  be 
adapted  to  numerous  kinds  of  work  of  similar  char- 
acter. 

Drill  Jig  for  an  Eccentric  Bushing.— The  eccentric 
bushing  shown  at  A,  Figure  127,  is  used  as  an  ad- 
justing bushing  for  obtaining  the  correct  relation 
between  the  worm  and  worm-gear  sector  of  an  auto- 
mobile steering  gear.  This  piece  of  work  has  been 
previously  bored  and  reamed  at  B,  and  has  been 
faced  on  the  end.  The  drill  jig  shown  in  the  illus- 
tration is  for  the  purpoae  of  drilling  the  hole,  D,  in 
the  end  of  the  arm  as  indicated  in  the  illustration. 
The  body  of  the  jig  is  provided  with  feet,  K,  on 


0Ij03£iD  11X08 


280 


TOOLS  AND  PATTBINS 


which  it  rests  on  the  table  of  the  driU  press.  The 
work  is  located  on  a  short  stud  shown  at  C,  and  is 
clamped  down  upon  the  shoulder  of  the  stud  by 
means  of  the  thumb  screw,  L.  This  thumb  screw 
operates  a  square  plate,  M,  which  bears  against  the 
top  of  the  bushing  at  E.  The  correct  location  for 
the  arm  in  which  the  hole  is  to  be  drilled  is  assured 
by  means  of  the  thumb  screw,  F,  which  acts  as  a  stop 
for  the  end  of  the  lever,  and  also  by  the  screw,  G, 
which  forces  the  work  over  against  the  screw  pre- 
viously  mentioned.  A  suitable  bushing  is  provided 
at  D,  which  is  so  arranged  that  it  can  be  removed 
and  replaced  by  another  bushing  of  suitable  size  for 
the  reamer. 

The  method  used  in  drilling  and  reaming  a  piece 
of  work  in  a  jig  of  this  kind,  is  first  to  drill  the 
work,  using  the  drill-sized  bushing,  and  immediately 
after  this  operation  to  remove  the  bushing  and  sub- 
stitute a  larger  one  of  the  proper  size  for  the  reamer. 
This  reaming  of  the  hole  sizes  it  correctly  to  the 
given  diameter  and  produces  a  smoothly  finished 
piece  of  work. 

The  slip  bushing  shown  in  this  iUustration  is  one 
of  many  types  which  can  be  used  when  it  is  neces- 
sary to  remove  one  bushing  and  replace  it  by  another, 
as  in  reaming  a  hole  after  it  has  been  drilled.  There 
is  very  little  difference  in  the  types  of  bushings,  the 
essential  point  in  design  being  that  the  bushing  shall 
be  so  made  that  it  can  be  easily  and  quickly  re- 
moved and  secured  firmly  when  in  position. 

Drill  Jig  for  a  Radius  Bracket.— A  somewhat  odd- 
shaped  piece  of  work  which  requires  a  rather  pecu- 


CLOSED  JIGS 


PIG.  128.    DRILL  JIG  FOB  A  RADIUS  BRACKET 


liar  type  of  jig  is  shown  in  Figure  128,  The  work,  A, 
has  been  previously  machined  on  the  surfaces,  B 
and  C,  to  the  angle  indicated.  It  is  necessary,  there- 
fore, to  locate  it  by  the  previously  finished  surfaces, 
and  also  to  provide  an  end  location  and  clamp  the 
work  securely  in  position  in  the  jig.  The  end  loca- 
tion is  assured  by  means  of  the  stop  screw,  E,  and 
by  the  thumb  screw,  Wm  This  thumb  screw*  F,  is 
hand  operated  after  the  work  has  been  thrown  over 


282 


TOOLS  AND  PAOTBBNS 


into  the  position  shown,  by  means  of  the  screw,  K,  at 
the  other  end  of  the  jig. 

The  work  to  be  done  in  this  operation  is  the  drilling 
of  the  hole,  D,  through  the  angular  side  of  the  piece, 
and  also  two  other  holes  indicated  at  B.  Suitable 
bushings  are  provided  for  all  of  these  holes,  as  can 
be  clearly  seen  in  the  illustration.   The  bushing  used 
for  the  hole,  D,  is  of  the  slip  variety  and  is  indi- 
cated at  G.  On  the  opposite  side  of  the  jig  a  bush- 
ing, H,  is  located  for  a  counterbore  which  is  used 
in  one  side  of  the  hole;  D.   In  operation  the  work  is 
placed  in  the  jig  until  the  surface,  B,  rests  against 
the  angular  part  of  the  jig,  after  which  the  set  screw, 
K,  is  used  to  move  the  work  forward  in  the  jig 
until  it  strikes  the  set  screw,  E.    The  thumb  screw, 
F,  is  then  brought  up  to  make  a  contact  and  to 
assist  in  supporting  the  work,  and  the  screw,  N,  is 
used  to  bring  up  the  angular  shoe  shown  at  L, 
against  the  angular  side  of  the  work.    The  work 
itself  rests  on  the  set  screws,  0  and  P,  and  is  clamped 
down  by  the  screw  at  M.   It  will  be  seen  that  the 
position  of  the  screw,  K,  is  such  that  it  tends  to 
throw  the  work  down  against  the  stop  and  over 
against  the  two  set  screws,  E  and  P.   A  jig  of  this 
kind  is  provided  with  feet  on  the  sides  opposite  to 
all  points  which  are  to  be  drilled,  so  that  the  jig 
will  have  a  firm  foundation  on  which  pressure  can 
be  brought  to  bear. 

In  drilling  tiie  pece  shown,  the  slip  bushing,  6, 
is  first  used,  and  a  large  hole  is  drilled  through  the 
portion,  D.  After  this  the  bushing  is  removed,  and  a 
counterbore  of  special  shape  is  fed  down  through  the 


CLOSED  jias 


283 


liner  bushing  indicated.  The  jig  is  then  turned  over 
and  the  process  is  repeated  through  the  bushing,  H. 
In  like  manner  the  other  holes  are  drilled  by  spindles 
in  a  multiple-spindle  drilling  machine,  these  spindles 
being  arranged  in  proper  location  to  give  the  correct 
spacing  for  the  various  holes.  Jigs  of  this  character 
are  used  for  many  kinds  of  work  and  can  be  adapted 
to  suit  different  conditions. 

Drill  Jig  for  a  Crooked  Lev^— The  work  shown 
at  A,  Figure  129,  is  a  crooked  lever,  both  ends  of 
which  are  to  be  drilled  and  reamed  as  shown  at  B 
and  C.  In  addition  to  these  two  holes,  there  is  a 
smaller  hole  at  F,  which  is  to  be  drilled  in  the  same 
setting  of  the  work.  For  this  operation  the  lever  is 
placed  in  the  jig  through  the  open  side  and  rests 
on  the  finished  pad  at  each  end.  At  the  large  end, 
the  flat  surface  of  the  work  rests  on  a  fixed  support, 
as  indicated,  but  at  the  smaller  end,  B,  the  support  is 
assured  by  means  of  the  screw  bushing  shown  at  H. 
After  the  work  has  been  placed  in  position,  this 
screw  bushing  is  jacked  up  by  means  of  a  pin  placed 
in  the  holes  shown  at  0. 

The  location  of  the  work  is  gained  by  the  V-blocks 
at  E.  It  will  be  noted  that  the  V-block  at  this  end 
of  the  lever  is  fixed,  but  at  the  other  end  there  is 
a  floating  member  attached  to  the  thumb  screw,  L, 
which  also  acts  as  a  V-block  locater.  This  is  clearly 
shown  in  the  upper  view.  After  the  work  has  been 
placed  in  position  and  located  as  mentioned,  the 
thumb  screw,  D,  is  turned  down  firmly  against  the 
web  of  the  lever.  The  work  is  now  in  position  to 
be  drilled,  and  the  jig  is  turned  over  on  the  legs 


284 


TOOLS  AND  PATTERNS 


FIG.  129.    OBILL  JIG  Wm  A  CROOKED  liEVER 

shown  at  P  and  K  for  the  various  drilling  operations 
involved. 

The  principles  involved  in  this  jig  are  identical 
with  those  which  can  be  applied  to  many  other 
varieties  of  lever  jigs.  Naturally  it  is  always  neces- 
sary to  adapt  any  jig  to  the  work  on  which  it  is  to 
be  used,  but  the  principles  underlying  the  design 
of  jigs  of  this  kind  are  much  the  same,  and  suitable 
adaptations  can  be  made  for  various  conditions  of 
work  in  the  shop. 

Large  Tnumioa  Jig.— When  the  work  to  be 
handled  is  of  large  size  and  somewhat  awkward  in 
shape,  it  is  sometimes  desirable  to  hold  it  in  some 


CLOSED  JIGS 


285 


sort  of  Jig  which  can  be  easily  loaded.  After  the 
piece  has  been  placed  in  the  jig,  the  entire  mechanism 
can  be  turned  over  by  means  of  a  crank  or  other 
mechanical  device,  so  that  it  will  lie  in  the  correct 
position  under  the  drill-press  spindles.  Furthermore, 
a  jig  of  this  kind  should  be  arranged  so  that  several 
sides  of  the  work  can  be  drilled  without  removing 
the  piece  from  the  jig  and  without  any  necessity 
for  more  than  one  operation  of  clamping.  A  suit- 
able indexing  device  can  be  made,  so  that  the  accu- 
racy of  the  holes  which  are  to  be  put  in  from  differ- 
ent sides  of  the  work  can  be  assured  without  diffi- 
culty. 

A  jig  of  the  Mnd  ntenlioiied  is  generally  termed  a 
trunnion  jig.  The  possibilities  of  a  trunnion  jig  are 
dependent  on  the  number  of  sides  of  the  work  which 
are  to  be  drilled.  When  the  work  is  such  that  it 
must  be  drilled  from  four  or  five  directions,  it  is 
possible  to  make  a  double  trunnion  jig  which  can  be 
indexed  in  several  directions  to  provide  for  the  drill- 
ing of  holes  from  several  different  angles.  However, 
a  jig  of  this  kind  is  more  or  less  complicated,  and  it 
does  not  always  prove  a  profitable  investment  to 
make  one  unless  the  work  is  in  sufficient  quantity 
so  that  the  expense  incurred  will  be  offset  by  the 
saving  in  the  manufacturing  time.  Nevertheless,  drill 
jigs  of  the  trunnion  type  having  a  suitable  bearing 
on  which  they  can  be  swung,  are  more  or  less 
common. 

An  example  of  a  trunnion  jig  of  this  kind  is  shown 
In  Figure  130.  The  work,  A,  in  this  case  is  a  trans- 
mission-case casting  made  of  aluminum  and  pre- 


286  TOOLS  AND  PATTERNS 


m.  130.    SZAMFUB  or  TRUNNION  JIG  fOB  A  TRANSHISSION 

CASE  C0¥1R 


viously  machined  along  the  surface,  C.  It  has  also 
been  drilled  at  two  points  for  dowels,  as  indicated 
at  By  and  these  holes  are  nsed  as  locating  holes  for 
the  work  when  the  piece  is  being  drilled.  In  locat- 
ing the  piece,  A,  in  the  jig,  the  position  of  the 
entire  jig  is  as  indicated  in  the  illustration.  The 
work  is  {daeed  in  the  XT-shaped  easting,  H,  locating 
on  the  dowel  pins  at  B.  After  it  has  been  placed  in 
position  the  latch,  F,  is  swung  down  into  position 
and  the  thumb  screw,  0,  is  tightened  to  secure  the 
latch.  After  this  the  two  thumb  screws  shown  at  D 
and  B  are  tightened  to  make  the  work  absolutely 
secure  in  the  jig. 

The  piece  is  now  ready  to  be  drilled,  but  it  will  be 
noted  ,  that  the  holes,  J,  which  are  to  be  drilled  are  in 
the  under  side  of  the  work.  The  entire  unit,  H,  is 
hung  on  two  bearings  at  S,  and  these  bearings  are 
situated  in  the  carriage,  L,  which  is  furnished  with 
wheels,  N,  traveling  along  a  track  located  on  the 
bed  of  the  drill  press.   An  enlarged  section  of  tlie 


diOSISD  JIGS 


287 


track  is  shown  at  P-Q,  which  makes  the  construc- 
tion of  this  part  of  the  jig  clearly  apparent.  The 
purpose  of  the  track  is  to  provide  a  means  of  mov- 
ing the  jig  from  one  machine  to  another  when  one 
part  of  the  work  has  been  drilled  by  a  series  of 
spindles  and  another  set  of  holes  is  to  be  handled  on 
another  machine. 

When  the  jig  is  to  be  indexed  preparatory  to  drill- 
ing, the  pull  pin,  K,  is  removed  from  the  bushed  hole 
indicated,  after  which  the  handle,  L,  is  operated, 
thus  indexing  the  entire  jig  by  means  of  the  gears 
shown  at  M.  This  indexing  operation  turns  the 
entire  jig  over,  so  that  it  is  in  the  correct  position  for 
drilling  the  work. 

An  arrangement  of  this  kind  will  show  very 
satisfactory  results  when  a  high  production  is  to 
be  obtained  on  a  given  piece  of  work  and  when  the 
piece  is  of  such  size  and  shape  that  it  can  not  be 
conveniently  handled  in  a  single  operation.  By  ar- 
ranging a  track  like  the  one  indicated  in  the  figurei 
and  by  suitably  fastening  this  track  on  cradle  cast- 
ings, like  those  shown  at  E,  the  round  shaft,  0,  makes 
an  exceUent  track  used  in  connection  with  the 
grooved  wheels.  It  is  entirely  possible,  with  an  ar- 
rangement of  this  kind,  to  set  up  two  or  three  ma- 
chines with  properly-spaced  spindles  so  that  the  jig 
can  be  rolled  from  one  machine  to  the  other  with 
very  little  loss  of  time  and  without  the  necessity  for 
more  than  one  setting  of  the  work. 

In  this  chapter  an  attempt  has  been  made  to  de- 
scribe' a  variety  of  drill  jigs  which  are  in  common 
use,  but  it  is  eivdent  that  it  is  entirely  out  of  the  ques- 


28aB  TOOLS  AND  PATTERNS 

tion,  in  a  work  of  this  kind,  to  go  into  every  matter 
of  design  in  great  detail.  Enough  examples  have 
been  given,  however,  to  make  the  subject  as  clear 
as  the  space  will  permit  and  the  examples  given  have 
been  selected  with  a  view  toward  simplicity  and 
variety* 


CHAPTER  XIX 


LUBRICATION  OP  CUTTING  TOOLS 

lecessity  of  Lubrication.— If  a  man  has  an  auto- 
mobile, a  bicycle,  or  some  other  piece  of  machinery 
and  wishes  the  machine  to  be  at  its  best,  the  irst 
thing  that  he  considers  is  the  proper  lubrication  of 
the  varions  bearings  so  that  the  mechanism  will  run 
as  smoothly  as  possible.  Now,  in  cutting  any  piece 
of  metal  the  question  of  lubrication  also  arises,  for 
as  the  cutting  tool  is  in  constant  contact  with  the 
metal  which  is  being  cut,  it  is  obvious  that  a  great 
deal  of  friction  is  produced.  The  friction  heats  the 
fool,  and  if  the  amount  of  heat  generated  is  excessive, 
the  result  will  be  disastrous  to  the  cutting  tool  and 
eventually  result  in  its  ruin.  It  is  necessary  there- 
lilre  on  some  Mnds  of  material  to  provide  a  suitable 
cutting  lubricant  in  order  to  carry  away  the  heat 
generated  by  the  friction  of  the  tool  and  to  make 
the  work  easier.  Certain  kinds  of  material  do  not 
require  lubrication,  but  on  others  it  can  be  used  to 
great  advantage. 

The  question  of  lubricating  a  cutting  tool  is  of  so 
great  importance  that  it  must  be  thoroughly  consid- 
ered. A  great  many  points  come  up  in  connection 
with  cutting  lubricants  for  different  classes  of  mate- 
rials. It  is  out  of  the  question  to  attempt  to  prescribe 


290 


TOOLS  AND  PATTERNS 


LUBRICATION  OF  CUTTING  TOOLS 


291 


a  cutting  lubricant  which  will  be  suited  to  any  par- 
ticular kind  of  metal  without  knowing  the  exact 
nature  of  the  alloy  of  which  the  metal  is  composed. 
Let  us  suppose  that  some  one  were  to  ask  the  question, 
"What  is  the  best  cutting  lubricant  for  aluminum?" 
It  would  be  difficult  to  answer  this  question  abso- 
lutely without  knowing  of  what  alloy  of  aluminum 
the  casting  was  composed. 

This  reminds  me  of  an  anecdote  which  I  once  heard 
of  two  Englishmen  who  were  in  this  country  for  the 
irst  time  and  who  were  talking  about  the  peculiar- 
ities of  Americans  in  general.  The  two  men  were  in 
a  railroad  station  at  the  time,  and  one  remarked  to 
the  other,  ''They  say  that  an  American  always  an- 
swers a  question  by  asking  another  one."  "That 
seems  very  improbable,"  replied  the  second.  **Well, 
let  us  see  if  this  is  really  the  case.  I'll  try  it  now." 
So  he  strolled  over  to  tke  ticket  office  and  asked  the 
ticket  agent,  want  a  ticket.  HoW  much  is  it?" 
And  the  agent  replied,    Where  to!" 

So  in  the  matter  of  cutting  lubricants  for  different 
materials,  if  I  were  asked  to  state  the  type  or* kind 
of  lubricant  best  suited  to  a  given  material,  I  would 
have  to  ask  what  the  composition  of  the  casting 
was  before  it  would  be  possible  to  name  the  proper 
kind  of  lubricant  to  use  on  the  work. 

There  is  considerable  difference  of  opinion  among 
manufacturers  as  to  what  particular  lubricant  is  bet- 
ter for  certain  classes  of  work.  However,  a  variety 
of  lubricants  have  been  proved  to  give  excellent 
results,  and  although  the  proportions  of  their  com- 
ponent parts  may  vary  somewhat,  the  ingredients 


themselves  are  very  similar.  In  this  chapter  we  will 
describe  a  number  of  lubricants  which  have  been  used 
with  success  on  different  kinds  of  materials.  Although 
modifications  of  the  formulas  herein  given  may  be 
found  advisable  in  some  cases,  the  ones  given  are 
thoroughly  practicable  for  commercial  purposes. 

Cromposition  of  Gutting  Lubricants.— In  the  first 
place  it  must'  be  remembered  that  all  materials  do 
not  require  lubrication.  Cast  iron,  for  example,  is 
not  lubricated  to  any  extent.  (Some  manufacturers 
have  attempted  to  use  various  lubricants  on  cast 
iron,  but  I  do  not  believe  that  the  results  obtained 
have  been  at  all  convincing.  At  any  rate,  cast  iron 
is  generally  cut  dry.)  Brass  is  usually  cut  dry. 
Aluminum  is  sometimes  cut  dry  and  at  other  times 
it  is  cut  with  a  lubricant. 

We  have  decided  that  the  purpose  of  a  cutting 
lubricant  is  twofold,  one  of  the  purposes  being  the 
lubricating  of  the  cutting  tool,  thereby  eliminating 
the  friction  to  a  certain  extent,  and  the  other  is  a 
cooling  action  intended  to  keep  the  cutting  tool  in 
such  condition  that  it  will  not  be  ruined  by  too 
great  heat.  Now,  in  discussing  the  kinds  of  lubri- 
cants used  for  these  purposes,  we  can  consider  that 
practically  only  two  kinds  of  lubricants  are  in  use. 
One  of  these  is  composed  of  lard  oil  or  mineral  oil, 
or  of  mixtures  of  mineral  and  lard  oil.  The  other 
compound  is  of  a  soapy  nature  and  was  devised  in 
order  to  provide  a  greater  cooling  effect  than  that 
obtained  by  the  use  of  oil  only;  at  the  same  time  it 
carries  sufficient  grease  so  that  it  provides  a  certain 
amount  of  lubrication  also. 


m  TOOLS  AND  PATTERNS 

A  solution  of  sodawater  was  formerly  used  as  a 
cooling  medium,  but  as  this  compound  possesses 
little  lubricating  action  it  bas  been  gradually  re- 
placed by  other  compositions  carrying  greater  per- 
centages of  grease.  A  number  of  solutions  are  on 
the  market  at  present,  and  most  of  these  are  in  the 
nature  of  emulsions.  A  saponaceous,  or  soapy,  fluid 
is  formed  by  means  of  potash,  or  soda,  added  to 
animal  oil  which  is  readily  soluble  in  water.  Li 
mixing  a  compound  of  this  kind  it  is  only  necessary 
to  dissolve  soap  in  mineral  oil  and  then  add  water 
sufficient  for  the  purpose  in  hand. 

It  is  important  in  mixing  a  solution  of  cooling  or 
cutting  compounds  for  any  kind  of  work  to  make 
sure  that  the  action  of  the  compound  is  not  such  that 
it  will  cut  away  the  lubricating  oil  used  in  the  bear- 
ings of  the  machine.  Unless  care  is  used  in  making 
a  proper  mixture,  there  is  some  danger  of  obtaining 
SO  "sharp"  a  mixture  that  it  will  eventually  remove 
all  the  lubricating  oil  from  whatever  portion  of  the 
machine  it  touches,  and  the  natural  result  will  be 
that  the  machine  itself  will  be  seriously  injured 
through  friction. 

The  different  compositions  of  cutting  lubricants 
as  used  by  various  manufacturers  are  much  the 
same,  although  their  method  of  mixing  and  the 
various  projKirtioMPiw  the  mgredients  may  differ 
somewhat.  In  general,  the  following  formulas  will  be 
found  to  give  good  results,  although  the  mixing  of 
the  compound  may  vary  according  to  the  amount  of 
water  which  is  used. 

Bar  stock  or  machine-steel  forgings  caa  best  be 


LUBRICATION  OF  CUTTING  TOOLS  293 

cut  with  a  mixture  of  lard  oil,  borax,  and  water,  or 
lard  oil  or  mineral  oil  can  be  used  alone. 

Steel  castings,  and  bronze  or  malleable  iron  can  be 
cut  to  advantage  with  a  lubricant  composed  of  min- 
eral oil  alone. 

A  mixture  made  of  half  lard  oil  and  half  kerosene 
will  prove  the  best  for  aluminum  castings,  and  pro- 
duces a  very  smooth  cutting  action  that  is  much 
better  than  kerosene  alone.  Kerosene  alone  is  advo- 
cated by  many  manufacturers,  but  it  is  not  equal  to 
the  lubricant  mentioned. 

Wide-faced  and  forming  tools  seem  to  give  better 
results  when  lard  oil  alone  is  used  with  them,  and 
tools  that  are  made  of  carbon  steel  seem  to  have 
longer  life  with  this  lubricant. 

Lubricating  Compound  for  SteeL— An  excellent 
borax  compound  for  steel  is  made  as  follows:  Dis- 
solve one  pound  of  borax  in  seven  gallons  of  hot 
water  and  allow  the  mixture  to  cool.  After  it  has 
cooled,  add  to  it  one  gallon  of  lard  oil  thoroughly 
mixed.  Enough  borax  should  be  used  to  make  the 
oil  and  water  mix  thoroughly.  The  quality  of  the 
lard  oil  used  will  affect  the  amount  of  borax,  and 
hard  or  soft  water  will  also  make  a  difference  in  the 
proportions.  The  quantities  mentioned  are  safe  to 
start  with,  although  slight  variations  may  be  needed 
to  suit  particular  cases. 

A  convenient  method  of  mixing  cutting  lubricants 
of  this  kind  is  to  use  forty  gallons  of  hot  water  to 
seven  pounds  of  borax,  mixing  the  solution  in  a  fifty- 
gallon  barrel.  When  the  solution  has  cooled,  seven 
gallons  of  lard  oil  can  be  stirred  in,  after  which  it  is 


294 


TOOLS  AND  PATTBKNS 


ready  for  use.  As  previously  mentioned,  the  greatest 
care  should  be  used  in  the  amount  of  borax,  because 
too  much  borax  has  a  tendency  to  cut  away  the 
lubricating  oil  used  on  the  machine,  so  that  trouble 
may  be  caused  from  imperfect  lubrication  of  the 
machine  parts.  In  general,  however,  it  will  be  found 
that  a  tool  will  wear  away  more  quickly  when  borax 
solution  is  used  than  if  pure  lard  oil  is  used,  but  the 
cooling  action  on  the  tool  is  considerably  greater 
with  the  borax  water. 

CkKding  by  Lubrication.— The  matter  of  cooling 
the  tool  and  lubricating  it  at  the  same  time  is  of  so 
much  importance  that  it  is  well  to  speak  at  this  time 
of  the  particular  necessity  for  proper  lubrication 
when  heavy  cuts  are  being  taken.  As  an  example,  let 
us  consider  that  a  piece  of  steel  is  being  cut  with  a 
heavy  feed  and  at  about  the  maximum  speed,  and 
it  is  desired  to  select  a  suitable  lubricant  for  it.  As 
the  friction  produced  by  a  heavy  cut  is  so  much 
greater  than  if  the  cut  were  to  be  a  light  one,  it  is 
apparent  that  in  order  to  produce  as  good  a  lubricat- 
ing effect  as  possible  it  will  be  necessary  to  use  an 
oil  rather  than  a  borax  compound.  But  if  the  same 
piece  of  steel  is  being  machined  at  high  speed  and 
the  amount  of  stock  which  is  being  removed  is  not 
very  great,  the  heating  of  the  tool  will  be  very  much 
greater,  and  a  borax  solution  will  therefore  be  found 
to  give  better  results. 

Another  factor  that  is  worthy  of  comment  in  re- 
gard to  the  use  of  cutting  lubricants  on  machine 
tools,  is  the  matter  of  power  consumption.  Author- 
itative data  on  this  subject  is  difl&cult  to  obtain,  but 


JiUBRICATlON  OF  CUTTING  TOOLS  ^  295 

as  it  is  known  that  a  machine  will  run  easier  with 
oil  in  the  bearings,  I  am  firmly  convinced  that  a  cut- 
ting tool  will  remove  metal  easier  if  it  is  properly 
lubricated.  Experiments  that  have  been  made  along 
these  lines  have  been  widely  different  in  the  results 
obtained,  and  to  my  knowledge  no  absolute  tests 
under  careful  management  have  been  made  that  give 
contradictory  data. 

Lubiicating  Stream  to  Remove  Chips.— Another 
function  which  should  be  mentioned  is  the  use  of 
a  stream  of  cutting  compounds  to  wash  away  the 
chips  that  are  generated  by  the  tool.  This  item  is 
more  serious  in  some  cases  than  in  others.  For  ex- 
ample, take  the  drilling  of  a  deep  hole  in  a  piece  of 
steel:  Here,  at  times,  it  is  difficult  to  get  the  chips 
that  are  being  rapidly  removed  out  of  the  way,  and 
they  stick  in  the  flutes  of  a  drill  or  pack  around  a 
cutting  tool  in  such  a  way  as  to  interfere  greatily 
with  the  proper  machining  of  the  piece. 

Let  us  take  as  an  example  a  piece  of  steel  which 
is  being  drilled  on  a  horizontal  turret  lathe.  Refer- 
ring to  Figure  131,  the  work.  A,  is  held  m  a  special 
collet  chuck  as  shown  in  the  illustration.  The  turret 
lathe  in  this  case  is  provided  with  a  system  for 
lubricating  the  tool  through  a  pipe,  B,  which  con- 
nects with  the  turret  as  it  is  indexed  from  one  posi- 
tion to  the  other.  The  drill,  C,  is  of  the  "oil  type," 
that  is,  it  has  a  hole  through  the  center  and  two 
ducts  which  lead  out  directly  at  the  point  of  the 
drill  through  which  the  cutting  lubricant  is  forced 
by  means  of  the  pump  on  the  machine.  As  the  pump 
forces  the  lubricant  to  tlve  drill,  the  high  pressure 


296  TOOLS  AND  PATTERNS 

4|l 


IIG.  131.    INTERNAL  OILING  ARRANGEMENT  FOR  DRILLING 
ON  A  HOftlZONTAL  TURRET  LATHE 


of  the  fluid  tends  to  force  out  the  chips  as  they  are 
generated  by  the  end  of  the  drill,  along  the  flutes,  so 
that  eventually  they  find  their  way  to  the  end  of  the 
work  and  drop  out.  A  method  of  forcing  lubricants 
through  tools  used  on  the  turret  lathe  is  not  uncom- 
mon, although  the  practice  varies  somewhat  with 
different  manufacturers.  Boring  bars  are  not  as 
easy  to  lubricate  as  some  other  forms  of  cutting 
tools. 

Lubricating  Through  the  Spindle  of  a  Turret 
Lathe.— The  device  shown  in  Figure  132  was  applied 
to  a  hclrizontal  turret  lathe  in  order  to  provide  proper 
lubricating  facilities  for  the  cutting  tools  used  in  the 
inside  work  on  the  piece,  A.  The  device  was  applied 
from  the  rear  end  of  the  spindl||||pit  the  pump  used 
to  force  the  lubricant  to  the  spinffle  was  a  component 


LUBRICATION  OF  CUTTING  TOOLS  pi 


HQ.  132.    LUBRICATION  OF  SPECIAL  NATURE  APPUED  TO  A 

TURRET  lATHE 


part  of  the  machine.  A  reference  to  the  illustration 
will  make  it  apparent  that  a  boring  bar,  B,  is  used 
to  bore  two  diameters  on  the  inside  of  the  work,  and 
is  piloted  by  a  bushing,  C,  in  the  chuck. 

In  order  to  provide  the  inside  cutting  tools  with 
proper  lubrication,  a  pipe,  D,  is  connected  to  the 
lubricant  supply  pump  and  is  passed  through  the 
end  of  the  spindle  where  it  is  guided  in  the  packing 
bushings.  Through  the  spindle  and  at  the  forward 
end,  E,  it  is  provided  with  a  telescoping  tube  of 
smaller  size,  as  shown  at  F.  This  smaller  tube 
reaches  forward  and  enters  a  hole  in  the  end  of  the 
boring  bar.  Prom  this  hole  other  smaller  holes  lead 
out  directly  in  front  of  the  cutting  tools.  A  coil 
spring  takes  care  of  the  variations  as  the  bar,  B, 
progresses  into  the  hole  during  the  cutting  action, 
and  a  stop  collar,  0,  limits  the  forward  movement 
of  the  tube,  F,  as  it  strikes  against  the  end  of  tie 
boring  bar. 

The  application  of  a  device  of  this  kind  to  a  turret 
lathe  is  not  costly,  and  the  results  obtained  by  its 


TOOLS  AMD  PATTBBNS 


LUBRICATION  OF  CUTTING  TOOLS 


2^9 


use  are  very  satisfactory.  At  different  times  I  have 
made  a  number  of  equipments  for  oiling  tools  through 
the  spindle,  most  of  which  have  been  on  a  similar 
order  to  th|M||  shown  in  this  illustration.  It  is 
obvioufii  tMHlKerent  conditions  require  slightly 
different  methods  of  handling,  but  the  principles  in- 
volved in  the  design  are  much  the  same  in  all 
cases* 

Fliiod  Lubrication. — ^Nearly  every  machine  of  a 
manufacturing  type  is  provided  with  lubricating 
devices  of  one  kind  or  another,  according  to  the  type 
of  machine  and  the  nature  of  the  work  to  be  donel 
A  turret  lathe  of  the  horizontal  variety,  for  instance, 
is  usually  equipped  with  outside  lubricating  devices 
which  will  direct  a  copious  supply  of  fluid  against  a 
piece  of  work  that  is  being  machined  A  milling 
machine  is  also  provided  with  an  outside  supply 
system  for  furnishing  cutting  lubricants  to  the  cut- 
ters and  the  work,  and  flood  lubrication  (which 
means  an  excess  supply  of  lubricants)  is  the  usual 
method.  The  production  of  work  from  machines 
which  are  provided  with  flood  lubrication  for  the 
cutting  tools  is  far  in  advance  of  that  obtained  from 
machines  of  the  older  type  which  had  an  inadequate 
supply  of  lubricant. 

In  order  to  supply  a  machine  with  a  proper  amount 
of  lubricant,  or  cutting  fluid,  and  to  direct  the  stream 
or  streams  to  the  proper  position,  it  is  necessary  to 
arrange  the  piping  in  such  a  way  that  the  spouts 
can  be  swung  in  any  direction,  longitudinally  and 
vertically.  By  referring  to  Figure  133  an  excellent 
6xa»qple  may  he  seen  of  the  application  of  a  cutting 


^0.  133.    OUmNO-IiUBRIGANT  SYSTEM  m  A  BWLA»D  VERTICAL 

TURRET  LATHE 


m 


TOOLS  AND  PAf  TEENS 


lubricant  system  to  a  vertical  turret  lathe.  This 
system  is  used  by  the  Bullard  Machine  Tool  Co.  on 
their  vertical  boring  mills  and  vertical  turret  lathes. 
A  standpipe  at  one  side  of  the  machine  contains  two 
sliding  tubes  which  can  be  adjusted  vertically  to  suit 
the  height  of  the  piece  that  is  being  machined.  These 
two  tubes  have  spouts,  A  and  B,  and  suitable  cocks, 
ais  shown  at  to  cut  off  the  lubricant  or  reduce  the 
flow.  It  will  be  seen  that  the  fluid  can  be  directed 
immediately  onto  the  work,  D,  without  difficulty. 

One  of  the  nice  features  of  the  device  shown  lies  in 
the  fact  that  the  supply  of  lubricant  is  copious  and 
can  flood  the  work  with  a  suitable  cutting  compound 
forced  through  the  pipe  by  a  pump  located  on  the 
machine.  After  the  cutting  fluid  has  been  used,  it 
flows  downwards  and  finds  its  way  eventually  through 
a  fine  screen  back  to  the  pump  and  is  immediately 
sent  forth  again  through  the  same  channel  to  the 
work. 


CUTTING  FEEDS  AND  SPEEDS 

A  Careful  Study  Eequired.— In  order  to  obtain 
maximum  efficiency  from  any  machine  tool  it  is  an 
essential  point  that  the  proper  cutting  feeds  and 
speeds  should  be  used.  The  question  then  arises  as 
to  what  cutting  speed  is  correct  for  any  given  kind 
of  material  with  a  given  feed.  It  is  evident  that  a 
very  little  difference  in  the  cutting  speed  and  a 
slight  variation  in  the  feed  used  on  a  piece  of  work 
will  make  considerable  difference  in  the  number  of 
pieces  of  work  that  may  be  produced  in  one  hour, 
one  day,  or  one  year. 

Let  us  suppose  that  a  certain  piece  of  work  is 
being  machined,  and  that  the  feed  and  speed  are  a 
little  less  than  they  should  be.  If  it  takes  an  oper- 
ator ten  minutes  to  produce  a  piece  of  work  at  the 
feed  and  speed  that  is  being  used,  then  a  reduction 
of  one  minute  in  the  time  necessary  to  machine  the 
piece  would  mean  a  considerable  saving  in  total  pro- 
duction time.  In  order,  then,  that  the  maximum 
production  should  be  obtained  from  any  machine,  it 
is  evident  that  the  cutting  feed  and  speed  should  be 
very  carefully  studied. 

Definition  of  Cutting  Speed. — The  term  cutting 
speed  in  feet  per  minute''  is  not  always  thoroughly 

m 


302 


TOOLS  AND  PATTEKNS 


understood  by  the  non-technical  man.  In  order  there- 
fore to  make  the  matter  more  clearly  evident  to  the 
reader  a  short  explanation  will  suffice.  Considered 
in  elementary  form,  cutting  speed  means  the  nnmber 
of  feet  of  metal,  considered  as  a  continuous  strip, 
which  passes  a  given  point  upon  the  edge  of  a  cut 
ting  tool  in  one  minute.  For  example:  Let  it  be 
supposed  that  I  am  planing  a  piece  of  cast  iron  5  feet 
long,  and  that  it  takes  me  10  seconds,  or  one-sixth  of 
a  minute,  to  make  a  cnt  the  length  of  the  work.  It 
is  evident  that  the  cutting  speed  which  I  am  using 
is  30  feet  per  minute,  because  it  takes  one-sixth  of 
a  minute  for  5  feet  to  pass  the  cutting  tool,  and  six- 
sixths  of  a  minute  will  elapse  while  30  feet  of  metal 
are  passing  the  tool,  not  considering  the  return 
stroke  of  the  planer. 

In  the  same  way  a  piece  of  cylindrical  work  which 
is  revolving  and  passing  a  given  point  on  the  cutting 
tool,  can  be  considered  as  a  ribbon  of  metal  unwind- 
ing from  the  outside  of  the  work  as  fast  as  it  passes 
the  tool.  In  this  case  the  circumference  must  be 
considered  in  determining  the  cutting  speed.  Let  us 
assume  that  I  have  a  piece  of  cast  iron  20  inches  in 
diameter  which  is  running  at  a  rate  of  10  revolutions 
per  minute,  and  I  wish  to  know  at  what  speed  1  anj 
cutting  the  work,  and  whether  it  should  be  decreased 
or  increased,  and  how  much. 

Formula  for  Determining  Cutting  Speeds.— -It  is 
evident  that  the  circumference  of  the  work,  multi 
plied  by  the  number  of  revolutions  per  minute  at 
which  it  is  running,  and  divided  by  12  (which  is 
the  number  of  inches  in  one  foot)  should  equal  the 


CUTTING  FEEDS  AND  SPEEDS 


number  of  feet  per  minute  at  which  the  work  is 
being  cut.  Or  the  solution  of  the  problem  would 
appear  as  follows: 

20 X 3.1416 X  10  ^ 

 12  =52.4  ft.  per  mm. 

As  this  process  is  a  rather  tedious  one,  let  us  take 
an  approximation  of  the  necessary  figures,  and  from 
them  derive  a  formula.  If  we  take  the  constant,  3.1416, 
and  divide  it  by  12,  which  is  the  number  of  inches 
to  the  foot,  we  obtain  the  figure  0.262,  or,  in  round 
numbers,  0.250.  Then  by  substituting  this  figure, 
0.250  (or  y^),  we  obtain  in  place  of  the  solution  of 
the  problem  given  above,  another  one: 

20  X  0.250  X 10  =  20  X  ^  =  50 

4 

While  this  is  not  exactly  correct,  it  is  near  enough 
for  all  practical  purposes. 

If  we  resolve  the  matter  into  a  formula,  then,  we 
obtain  the  following: 

D  X  C 

Where 
D  =  diameter  of  work. 

N  =  number  of  revolutions  per  minute.  , 
C  =  euttiiig  speed  in  feet  per  minute. 

If  we  reverse  this  process  in  order  to  find  the 
necessary  number  of  revolutions  per  minute  required 
for  a  piece  of  work  of  a  given  diameter  to  obtain  a 
given  cutting  speed,  we  use  the  formula 

^  ^  ^  %i 


304 


TOOLS  AND  PATTERNS 


TakiBg  the  same  example  as  given  above  with  the 
work  diameter,  D  =  20;  cutting  speed  desired,  C== 
50  feet  per  minute,  then 

4x50 

— ^ — =  10  r.p.m. 
20 

It  will  be  found  that  most  of  these  formulas  are 
very  simple  and  can  easily  be  memorized,  so  that 
all  cutting  speeds  for  any  given  diameter  can  be  de- 
termined very  rapidly  by  mental  calculation. 

The  number  of  revolutions  required  to  obtain  cut- 
ting speeds  for  given  diameters  can  be  found  in  any 
mechanical  handbook,  but  such  a  book  is  not  always 
conveniently  at  hand  when  it  is  desired  to  know 
what  a  cutting  speed  is  for  a  certain  class  of  work. 
In  such  cases  the  above  formulas  will  be  found  of 
great  assistance. 

Relation  of  Speed  to  Feed.— There  are  certain  well- 
defined  rules  which  can  be  applied  to  the  correct  set- 
ting of  a  feed  and  speed  for  a  given  piece  of  work 
when  the  composition  and  the  quality  of  the  work  are 
known.  An  important  factor  in  production  work  is 
the  depth  of  the  cut  to  be  taken  on  the  work.  If  a 
large  amount  of  material  is  to  be  removed,  and  if,  there 
fore,  the  depth  of  the  cut  is  considerable,  it  is  evi- 
dent that  the  amount  of  pressure  brought  to  bear 
upon  the  tool  and  the  amount  of  power  required  to 
pull  tiie  tool  through  the  work  are  of  first  impor- 
tance. 

Speaking  generally,  the  depth  of  the  cut  has  a 
powerful  effect  on  the  feed  which  can  be  used  and 
also  on  the  speed.  It  would  seem  that  there  should 


CUTTING  FEEDS  AND  SPEEDS  305 


be,  then,  a  direct  relation  between  the  cutting  speed 
and  the  feed.  That  is  to  say,  if  a  speed  of  fifty  feet 
per  minute  were  to  be  used  and  a  feed  of  1/32  of 
an  inch  per  revolution  of  the  work  with  a  depth  of 
cut  of  1/8  of  an  inch,  it  would  appear  logical  that  if 
the  cutting  speed  were  to  be  changed,  the  amount  of 
feed  would  need  to  be  changed  also.  Just  how  much 
change  a  variation  of  ten  or  fifteen  per. cent  in  the 
cutting  speed  would  be  required  in  the  feed  in  order 
to  produce  the  same  results  with  the  same  amount  of 
damage  or  injury  to  the  tool,  is  a  difficult  question 
to  decide. 

However,  the  amount  of  stock  to  be  removed  from 
a  casting  or  a  forging  is,  in  the  majority  of  cases, 
very  nearly  uniform  when  the  work  is  to  be  put 
through  the  shop  on  an  interchangeable  basis.  We 
shall  assume  in  our  discussion  of  cutting  feeds  and 
speeds,  then,  that  the  amount  of  stock  to  be  removed 
from  any  given  piece  of  work  is  according  to  the 
usual  practice.  Speaking  generally,  the  larger  a 
piece  of  work  is,  the  more  stock  is  left  to  be  re- 
moved by  the  cutting  tool,  because  on  large  work, 
variations  in  the  casting  are  more  likely  to  be  found. 

On  a  piece  of  cast  iron,  six  inches  in  diameter,  the 
ordinary  amount  of  finish  left  on  the  casting  would 
not  be  apt  to  exceed  %  of  an  inch  on  a  side.  On 
work  30  inches  or  more  in  diameter,  there  might 
easily  be  from  %  to  %  of  an  inch  of  stock  to  be 
removed.  It  is  very  apparent,  then,  that  in  ma- 
machining  large  work  the  depth  of  the  cut  would 
need  to  be  deeper  and,  therefore,  the  feed  would 
not  be  apt  to  be  so  great. 


306 


TOOLS  AND  PATTERNS 


But  there  are  other  faetors  which  enter  into  the 
machining  of  any  piece,  and  these  factors  sometimes 
seem  to  contradict  themselves.  In  the  machining  of 
a  large  casting,  30  inches  or  more  in  diameter,  with 
a  depth  of  cut  %  of  an  inch,  it  might  be  entirely 
possible  to  take  a  feed  even  a  little  greater  than 
would  be  possible  on  a  small  piece  six  inches  in 
diameter.  .The  factors  which  would  influence  this 
matter  are  the  power  of  the  machine,  the  weight 
and  rigidity  of  the  work  which  is  being  machined, 
and  the  sectional  area  of  the  tool  which  is  doing  the 
work.  The  area  of  the  tool  would  be  proportionately 
greater  on  a  heavy  and  large  machine  than  on  & 
small  machine. 

Conservative  Cutting  Speeds. — ^It  will  be  noted 
from  the  foregoing  statement  that  the  amount  of  feed 
and  speed  which  can  be  used  on  a  given  piece  of 
work  is  not  by  any  means  an  absolutely  fixed  amount. 
Given,  however,  a  comparatively  uniform  amount  of 
stock  to  remove  from  a  casting  of  a  known  degree 
of  hardness,  there  are  certain  conservative  feeds  and 
speeds  which  can  be  used  with  safety.  It  is  always 
necessary  in  making  an  estimate  of  production  on  a 
given  piece  of  work,  to  assume  a  certain  cutting  feed 
and  speed  which  has  been  found  by  long  experience 
to  be  within  the  limit  of  safety. 

Assuming  that  the  metals  to  be  cut  have  been 
pickled  or  sand-blasted  to  remove  any  injurious 
scale  that  may  be  upon  fheni  prior  to  the  machin- 
ing operaton,  and  further  assuming  that  the  amount 
of  stock  to  be  removed  is  not  excessive,  the  follow- 
ing table  of  cutting  speeds  for  different  materials 


CUTTING  FEEDS  AND  SPEEDS 


307 


will  be  found  to  give  results  well  within  the  limit  of 
safety.  It  is  always  well  in  making  an  estimate  of 
production  on  a  given  piece  of  work,  to  assume  that 
the  work  is  normal  and  not  very  hard,  and  that  it 
has  no  excessive  material  to  remove.  Under  these 
circumstances,  after  an  estimate  of  production  has 
been  made,  it  is  easily  possible  to  speed  up  a  ma- 
chine slightly  in  order  to  gain  a  little  in  production, 
providing  the  material  which  is  being  cut  proves  to 
be  of  such  a  quality  that  it  permits  a  little  higher 
speed  than  normal. 

Cast  iron — 50  feet  per  minute. 
Cast  steel — 60  feet  per  minute. 
Malleable  iron— 70  feet  per  minute. 
Machine  steel  forgings  (15  to  20  point  carbon) — 65  feet 
per  minute. 

Machine  steel  (black  stock) — 70  feet  per  minute. 

Tool  steel  forgings— 35  to  40  feet  per  minute. 

Sted  alloys  (containing  nickel  and  chromium)— 30  to  50 

feet  per  minute  (depending  on  alloy). 
Yellow  brass— 200  feet  per  minute: 
Composition  brass— 120  to  150  feet  per  minute. 
Bronzes— 30  to  80  feet  per  minute  (depending  on  alloy). 

Importance  of  Proper  Speeds  and  Feeds.— The  im- 
portance of  a  correct  cutting  speed  and  feed  cannot 
be  overestimated.  It  is  safe  to  say  that  the  afHHW 

manufacturer  loses  more  money  in  the  course  m  a 
year  by  incorrect  setting  of  speeds  and  feeds  in  his 
factory  than  by  any  other  single  item  in  his  total 
outlay. 

A  number  of  reasons  are  responsible  for  this,  but 
probably  the  most  usual  one  is  the  fact  that  no  work- 


308 


TOOLS  AND  PATTERNS 


CUTTING  FBBDS  AND  SPEEDS 


ao9 


man  likes  to  grind  tools.  If  a  workman  has  a  num- 
ber of  pieees  of  work  to  do  on  a  maehine  which  re- 
quires rather  careful  ** setting  up,"  he  is  quite  apt 
to  run  his  machine  a  little  too  slowly  so  that  it  will 
not  be  meessary  for  him  to  grind  the  tools*  very 
often. 

It  is  the  duty  of  any  foreman  of  a  department 
in  a  factory,  to  make  sure  that  the  production  time 
on  the  work  in  process  is  as  great  as  the  nature  of 
the  work  will  permit.  It  is  furthermore  the  duty 
of  the  progressive  executive  to  make  certain  in  his 
own  factory  that  he  is  obtaining  the  results  that  he 
should  obtain  by  making  a  personal  examination 
of  the  methods  in  use  from  time  to  time,  and  to  keep 
himself  posted  in  regard  to  the  work,  so  that  produc- 
tive inefiSeieney  shall  not  be  laid  to  a  lack  of  knowl- 
edge on  his  part. 

Allowance  for  Exceptional  Cases. — ^While  it  is  all 
very  nice  for  a  tool  engineer,  an  executive,  or  a  fore- 
man in  a  factory  to  determine  positively  beforehand 
exactly  at  what  speed  any  piece  of  work  must  be 
run,  it  is  an  entirely  different  proposition  to  tell  the 
man  in  the  factory  who  is  doing  the  work  that 
h^  must  mn  that  work  at  exactly  the  prescribed 
speed  and  feed.  Getting  back  to  first  principles,  it 
would  be  entirely  possible  to  fix  absolutely  every 
cutting  speed  and  feed  in  the  factory,  providing  the 
material  which  was  being  cut  were  exactly  of  the 
same  quality  in  each  and  every  case.  Unfortunately, 
however,  foundry  practice  is  not  such  as  to  give  abso- 
lutely certain  results.  Sometimes  a  group  of  castings 
will  be  fopad  very  hardi  while  in  other  cases  they  will 


be  soft.  It  is  evident  that  the  first  group  cannot  be 
machined  as  rapidly  as  the  second. 

In  these  days  of  rapid  production  and  high  speed, 
it  frequently  happens  that  several  patterns  are  made 
of  the  same  piece  of  work,  and  in  order  to  obtain 
the  castings  as  rapidly  as  possible,  the  patterns  are 
sent  to  different  foundries.  Invariably  the  castings 
from  one  foundry  will  differ  in  some  respect  from 
those  of  another  foundry,  and  due  allowance  in  set- 
ting speeds  and  feeds  must  be  made  for  such  condi- 
tions. So  also  in  the  case  of  alloy  steels,  a  very  great 
difference  may  be  found  in  two  lots  of  forgings,  al- 
though in  this  case  the  trouble  is  not  caused  by  the 
composition  as  a  general  rule,  but  is  more  likely  to 
be  the  result  of  an  improper  treatment  of  the  forg- 
ings after  they  have  been  made. 

The  remedy  for  conditions  of  this  kind  is  apparent. 
It  is  certainly  not  the  part  of  economy  for  the  manu- 
facturer to  reduce  his  production  speed  just  because  a 
foundryman  or  a  drop-forge  department  has  made 
errors,  or  has  neglected  to  do  some  of  the  things  that 
should  have  been  done  before  the  castings  or  forgings 
were  delivered.  However,  it  may  happen  that  the 
manufacturer  does  not  feel  disposed  to  send  back  a  lot 
of  imperfect  or  improperly  treated  castings  or  forg- 
ings, and  prefers  to  machine  them  as  they  are.  In 
such  a  case  he  will  have  to  establish  arbitrary  ma- 
chining speeds,  and  his  decisions  must  be  governed 
by  the  conditions. 

Effect  of  Lubricant  on  Feed  and  Speed. — ^In  the 
previous  chapter  the  matter  of  cutting  lubricants 
was  discussed  and  various  data  were  given  in  regard 


310 


TOOLS  AND  PATTllNS 


to  the  most  suitable  lubricant  for  various  classes  of 
materials.  In  tool-room  work,  however,  it  is  very 
often  the  case  that  the  workman  does  not  wish  to 
use  a  lubricant  in  cutting  a  piece  of  metal.  This 
is  largely  because  the  use  of  a  lubricant  results  in 
much  dirtier  work,  which  is  difficult  to  handle.  Hence, 
the  toolmaker  prefers  to  cut  his  work  dry  as  a  gen- 
eral thing.  There  is  no  particular  reason  why  a 
workman  on  this  class  of  work  should  not  use  his 
own  judgment  as  to  lubricants.  He  might  be  able 
to  produce  some  classes  of  work  more  rapidly  by 
using  them,  because  he  could  use  a  little  higher  speed 
and  a  little  more  feed,  but  in  the  long  run  no  par- 
ticular gain  would  be  found.  Of  course,  in  making 
heavy  roughinqo^  cuts  in  the  tool  room,  or  anywhere 
else  in  the  factory,  a  lubricant  will  undoubtedly  be 
found  of  great  advantage.  In  the  table  given  pre- 
viously in  this  chapter,  it  is  assumed  that  a  proper 
lubricant  is  to  be  used  on  work  which  needs  lubrica- 
tion. 

General  Rules.— Speaking  generally,  the  amount  of 
feed  and  speed  to  be  used  for  any  work  produced 
in  quantities!  should  be  as  great  as  the  work  will 
permit  without  obliging  the  workman  to  re-grind  his 
tool  more  than  three  times  in  one  day.  Naturally, 
there  are  exceptions  to  this  rule,  but  as  a  general 
thing  if  the  workman  is  not  obliged  to  grind  his  tool 
oftener  than  once  a  day,  he  is  losing  time  in  produc- 
tion. But,  on  the  other  hand,  if  the  workman  finds  it 
mmmmm  to  re-grind  his  tool  about  once  every  hour, 
Wtrnmre  indication  that  the  speed  is  too  rapid  or 
the  feed  is  too  deep. 


CUTTma  FEEDS  AND  SPEEDS  311 


I  recall  a  rather  peculiar  incident  connected  with 
the  use  of  the  proper  cutting  speed  and  feed  that  hap- 
pened some  years  ago.  In  passing  through  a  factory, 
Tworkman  stopped  me  and  asked  if  I  could  tell  him 
what  kind  of  steel  he  could  use  in  place  of  the  tool 
he  then  had.    On  questioning  the  man  it  appeared 
that  he  was  grinding  the  tool  after  he  had  produced 
about  two  pieces,  and  this  tool  grinding  kept  him 
busy  for  some  minutes  each  time.  On  examining  the 
work,  I  found  it  to  be  a  piece  of  bronze  about  4 
inches  in  diameter.    The  workman  proceeded  to  cut 
one  of  the  pieces  while  I  was  standing  by  his  side.  1 
noticed  that  the  speed  seemed  to  be  excessive,  and 
by  counting  the  number  of  revolutions  per  minute,  i 
saw  that  he  was  running  the  work  at  something  over 
600  feet  per  minute.    As  the  work  was  a  piece  of 
manganese  bronze,  it  is  evident  that  the  tool  was 
being  ruined  about  as  fast  as  he  could  ^^f^^ 
After  he  had  reduced  the  speed  to  about  100  feet 
per  minute  he  had  no  further  difficulty  with  the  tool. 
This  example  simply  illustrates  conditions  which 
sometimes  obtain  in  a  factory  on  account  of  the  igno- 
rance or  carelessness  of  the  worker. 

As  it  is  absolutely  impossible  to  set  a  cutting  speed 
or  feed  for  a  piece  of  work  without  making  a  trial 
to  see  whether  the  work  is  hard  or  soft,  it  t>f  ooves 
every  factory  manager  or  executive  to  see  that  the 
greatest  care  is  used  in  making  these  determinations. 
After  the  speeds  and  feeds  have  been  set  as  nearly 
correct  as  possible,  it  is  well  to  make  an  examination 
to  prove  that  the  results  show  that  the  work  is  being 
produced  to  the  best  advantage.  The  foreman  should 


S12 


TOOIiS  Am  PATTERNS 


test  the  various  maebines  from  time  to  time  in  order 
to  make  sure  that  the  maximum  efficiency  is  being  ob- 
tained. For,  next  to  proper  cutting  tools,  speeds  and 
feeds  are  of  first  importanee.  In  order,  then,  to  see 
that  the  factory  is  obtaining  the  maximum  output, 
all  these  various  points  must  be  considered,  and  each 
one  must  be  planned  in  such  a  way  that  there  will  be 
mo  loss  either  from  incorrect  handling,  from  improper 
setting  of  tools,  or  from  incorrect  speeds  and  feeds. 
When  all  these  matters  have  been  looked  into  by  the 
proper  men,  the  executive  can  feel  assured  that  he  is 
obtaining  the  full  capacity  of  the  machine,  and  when 
he  has  done  this  he  has  approached  closely  to  max- 
imum efficiency. 


CHAPTER  XXI 


PLANNING  AND  LAYING  OUT  WORK 

# 

Business  Aspects  of  Planning.— If  a  man  were 
about  to  build  a  house,  his  first  step  would  be  to  de- 
termine what  kind  of  house  he  wanted.  He  would 
devote  considerable  time  in  sketching  out  certain  ar- 
rangements  of  rooms,  and  after  he  had  determined 
about  how  many  rooms  he  wanted  and  how  much  he 
wanted  to  pay  for  the  house,  he  would  take  his 
sketches  io  an  architect  who  would  draw  up  a  set 
of  plans  from  them.  After  the  architect  had  planned 
the  house  carefully,  he  would  make  an  estimate  on 
the  cost  of  the  various  building  operations.  That  is 
to  say,  he  would  estimate  the  amount  of  excavation 
required  for  cellar  and  foundations  and  the  cost  of  all 
other  matters  connected  with  the  actual  building. 
He  would  then  submit  his  plans  to  a  number  of  car- 
penters and  builders  and  obtain  bids  from  them.* 

At  least,  this  is  the  procedure  that  would  be  fol- 
lowed by  the  average  man;  but  here  and  there  one 
will  find  a  peculiarly  constituted  individual  who, 
quite  probably,  would  take  his  rough  ideas  to  a  car- 
penter and  say,  **Here  are  some  ideas  of  a  house  I 
want  built.  Go  ahead  and  build  it  like  that."  The 
resulting  house  can  readily  be  imagined. 

*  Full  discussUm  of  the  mechanism  of  planning  wiU  be  found  in 
l^lanning  and  Time  Study,  hy  O.  S.  Armstrong,  Factory  Management 
Course. 

813 


TOOLS  AND  PATTERNS 


In  any  kind  of  business  venture  involving  the  out 
lay  of  a  number  of  dollars,  a  business  man  would  be 
sure  to  investigate  thoroughly  all  matters  connected 
with  the  project.  In  fact,  in  any  buying  or  selling 
proposition,  the  man  whose  money  was  to  be  used 
would  be  apt  to  look  up  every  point  in  connection 
with  the  spending  of  his  money.  So  also  in  the  manu- 
facture  of  any  kind  of  product,  it  is  of  the  first  im- 
portance to  study  the  methods  of  production  that 
are  to  be  used  and  to  plan  carefully  in  advance  all 
of  the  operations  necessary  to  complete  the  various 
parts  for  the  finished  product. 

The  importance,  then,  of  the  planning  department 
in  manufacturing  can  readily  be  seen.  It  would  cer- 
tainly be  the  height  of  folly  for  any  manufacturer 
to  go  ahead  and  obtain  a  great  number  of  castings, 
forgings  and  other  material  from  which  the  various 
parts  were  to  be  manufactured,  and  then,  without 
further  thought  about  the  matter,  to  put  these  parts 
out  into  Ms  factory  without  any  particular  plan  or 
scheme  of  operation  in  his  mind.  And  yet  in  many 
cases,  especially  in  old-established  factories,  the  mat- 
ter of  planning  and  laying  out  the  various  operations 
for  any  given  piece  of  work  is  almost  entirely 
neglected.  It  is  true  that  the  operating  official,  in 
cases  of  this  kind,  depends  largely  upon  his  foreman 
and  workmen  to  step  into  the  breach  and  produce  a 
finished  piece  of  work  which  resembles  the  mechanism 
which  he  is  attempting  to  build.  In  the  progressive 
factory,  however,  the  planning  department  receives 
the  most  careful  attention,  and  the  .men  who  are  at 
the  head  of  it  are  specially  trained.  In  addition,  their 


PLANNING  AND  LAYING  OUT  WORK  315 


long  experience  enables  them  to  plan  in  advance 
every  detail  of  the  work  to  be  done.  In  no  other  way 
can  the  greatest  efficiency  be  obtained  from  any  fac- 
tory, and  although  the  outlay  necessary  for  a  well 
organized  planning  department  is  fairly  large,  the 
results  obtained  more  than  offset  the  expenditure. 

One  of  the  best  examples  of  careful  planning  can 
be  found  in  the  Ford  Motor  Company  plant  in  De- 
troit. Were  it  not  for  the  care  and  forethought 
which  has  been  used  throughout  this  factory,  it  would 
have  been  impossible  to  obtain  the  tremendous  pro- 
duction of  these  Ford  cars. 

Tool  Engineering  Methods. — The  importance  of  tool 
engineering  has  only  recently  been  brought  to  the  at- 
tention of  the  manufacturer.  A  few  years  ago  the 
tool  designer  in  a  factory  was  supposed  to  lay  out 
the  various  operations  on  the  work  which  was  to  be 
done,  but  this  laying  out  of  operations  was  in  the 
main  a  rather  unfinished  procedure.  It  is  true  that 
the  old-fashioned  tool  designer  would  make  a  rough 
layout  of  operations  necessary  to  complete  a  certain 
piece  of  work,  but  he  would  not  go  into  the  matter 
very  thoroughly.  The  method  used  by  the  modem 
tool  engineer,  however,  is  such  that  every  point  in 
the  manufacture  is  taken  up  with  the  greatest  care 
and  nothing  is  left  to  chance.  All  the  operations 
which  are  to  be  done  on  the  wojrk  are  simply  planned 
in  accordance  with  the  equipment  of  the  factory. 
More  than  this,  the  equipment  (if  it  is  insufficient  to 
do  the  work  required)  is  added  to,  in  order  that 
maximum  efficiency  on  the  work  in  process  may  be 
obtained. 


316 


TOOLS  AND  PATTEBNS 


The  matter  of  planning  is  of  such  great  importance 
that  I  intend  to  take  it  up  in  this  book  in  consider- 
able detail  I  believe  that  the  best  way  to  describe 
the  methods  used  and  the  processes  which  are  ap- 
plied by  the  tool  engineer,  is  to  describe  the  various 
steps  which  are  taken.  In  order  that  the  subject  may 
be  as  dear  as  posmblcy  let  m  assume  that  a  modem 
factory,  very  well  equipped  with  machine  tools  of 
good  design — one  which  has  been  used  for  automobH 
work — ^is  about  to  proceed  with  the  manufacture  of 
a  new  model,  and  that  the  drawings  of  the  complete 
mechanism  have  been  handed  over  to  the  tool  engi- 
neer ready  for  him  to  design  the  tools  and  fixtures 
for  the  work  which  is  to  be  done.  Let  us  also  assume 
that  the  tool  engineer  has  been  employed  by  the  same 
company  for  several  years,  so  that  he  is  thoroughly 
familiar  with  the  machine  tool  equipment. 

Let  us  follow  the  steps  taken  by  the  tool  engineer 
in  this  work,  noting  the  various  points  of  impor 
tance,  which  will  be  discussed  at  length  later  in  this 
chapter.  Let  us  assume,  then,  that  the  tool  engineer 
has  a  pile  of  blue-prints  on  his  desk — ^he  picks  up 
one  of  the  important  pieces  (usually  one  of  good 
size  and  considerable  importance),  and  takes  up  the 
points  logically  about  as  follows: 

1.  — ^Looks  over  each  blue-print,  compares  it  with 
the  assembly  drawing,  and  notes  the  important  fits, 
the  relation  of  the  piece  in  question  to  the  other 
parts  of  the  mechanism,  and  so  on. 

2.  — ^Makes  rough  notes  of  the  various  operations 
necessary  for  the  completion  of  the  work. 

3. — Looks  over  the  machine-tool  equipment  of  the 


817 


factory,  to  see  what  machines  are  best  adapted  to 
produce  the  work  necessary. 

4.  — ^Determines  the  jigs  and  fixtures  needed  in  the 
work  of  production,  notes  gauges  necessary,  and  also 
the  accuracy  required  for  the  various  fits. 

5.  — ^Lays  out  the  operation  sheet  in  detail. 

6.  — Makes  rough  pencil  sketches  of  jigs,  fixtures 
and  other  tools  necessary  in  the  production. 

7.  — ^Makes  layout  sheets. 

8.  — ^Makes  time-studies  from  layout  sheets. 

9. — Designs  jigs,  fixtures,  and  special  tools,  together 
with  gauges  needed  for  the  work. 

10.  — ^Notes  number  of  machines  required,  deter- 
mined by  the  time-studies  made  for  the  various  oper- 
ations. 

11.  — ^Tums  over  the  time-study  sheets  to  the  cost 
department,  in  order  that  piece-work  prices  may  be 
set  from  the  estimated  time  of  production. 

Now  these  various  steps  which  are  taken  by  the 
tool  engineer  are  not  all  undertiiten  at  once,  but  ap- 
proximately in  the  sequence  just  given,  although  the 
practical  engineer  is  often  able  to  combine  several 
at  a  time.  Let  us  now  take  up  each  of  the  points  in 
detail. 

1:  Preliminary  Processes. — Now  in  the  first  step 
which  the  tool  enginetftalkiikes,  he  makes  a  rather  rough 
analysis  of  the  work  which  is  to  be  done,  but  he  does 
try,  in  this  preliminary  inspection,  to  grasp  the  im- 
portant details  of  the  construction  and  obtain  a  very 
good  general  idea  of  what  lies  before  him.  In  addi- 
tion to  this,  he  familiarizes  himself  with  the  general 


TOOLS  AND  PATTERNS 


points  in  the  construction  of  the  mechanism  which 
he  is  to  build,  by  an  inspection  of  the  assembly  draw- 
ings. He  studies  these  assembly  drawings  carefully, 
in  order  to  learn  the  general  construction  of  the  en- 
tire mechanism  of  which  the  piece  shown  on  the  blue- 
print that  he  is  examining,  is  a  component  part.  He 
notes  very  carefully  whether  certain  of  the  parts 
should  be  a  tight  fit,  or  whether  they  should  be  a 
sliding  or  a  running  fit,  and  he  determines  the  im- 
portance  of  their  relation  to  the  entire  mechanism. 
After  the  tool  engineer  has  gone  over  a  few  pieces 
of  work  in  this  way,  he  begins  to  form  a  very  good 
idea  of  the  work  which  he  is  about  to  do.  He  is  now 
ready  for  the  second  step  in  the  process. 

2:  Preliminary  Layout  of  Operation.— Taking  up  the 
piece  now  in  detail,  the  tool  engineer  roughly  plans 
the  operations  which  are  necessary  for  the  comple- 
tion of  the  work,  and  makes  notes  in  pencil  in  the 
form  of  a  memorandum,  by  which  he  is  guided  when 
he  makes  the  more  serious,  careful  planning.  For 
example,  he  makes  a  note  to  this  effect  on  his  mem- 
orandum pad:  **This  piece  must  be  chucked,  the  hub 
must  be  turned,  and  the  inside  must  be  bored  out  on 
a  turret  lathe.  The  other  end  of  the  work  also  must 
be  fiiiished  and  turned,  requiring  another  screw-ma- 
chine or  a  turret-lathe  operation.  There  are  to  be 
six  drilled  holes  around  the  flange  of  the  piece,  and 
these  must  be  bored  in  a  drill  jig  on  a  multiple- 
spindle  drilling  machine.  There  are  also  several 
other  operations  of  milling  and  counterboring,  and 
perhaps  even  one  or  two  besides  these."  In  any  event, 
the  tool  engineer's  memorandum  on  this  work  will 


FhANNWQ  AND  LAYING  OUH  WOEK  319 

cover  everything  which  is  to  be  done  to  the  piece, 
hut  it  may  be  that  the  operations,  as  noted  by  him, 
may  not  be  in  the  sequence  to  produce  the  piece  to 
the  best  advantage.  This  matter  will  be  taken  up 
later  as  the  careful  layout  of  operations  is  made. 

3:  Kadiiiie-Tool  Iquipment.— Now  it  must  be 
understood  that  although  the  points  mentioned  are 
given  in  sequence,  in  reality  often,  as  I  have  said, 
many  of  these  points  are  taken  up  by  the  tool  engi- 
neer at  the  same  time,  since  he  is  trained  to  this 
kind  of  work,  and  therefore  when  he  thinks  of  a 
piece  of  work  or  an  operation  which  is  to  be  done 
on  a  given  piece  of  work,  his  mind  automatically 
selects  the  type  of  machine  which,  in  his  estimation, 
is  most  suited  to  the  work  in  hand.  He  also  is  pos- 
sessed of  a  knowledge  of  the  various  machine  tools 
which  the  factory  has  on  hand,  and  knows  something 
about  their  condition  and  their  adaptability  to  cer- 
tain classes  of  work.  It  is  obvious,  however,  that 
in  a  large  factory  the  tool  engineer  cannot  carry  all 
of  these  details  in  his  mind,  so  that  it  is  necessary 
for  him  to  have  a  complete  record  of  the  machine 
tools  contained  in  the  factorv. 

This  matter  brings  us  to  the  point  of  a  reference 
machine-tool  index,  whieh  every  progressive  tool  en- 
gineer must  have.  The  amount  of  detail  contained 
m  a  record  of  this  kind  is  governed  by  the  size  of 
the  factory  and  the  kind  of  product  which  is  being 
manufactured.  It  is  evident  that  in  a  small  factory 
It  would  be  comparatively  unnecessary  to  have  a  de- 
tailed record  of  every  machine  tool  in  the  shop,  with 
Its  feeds,  speeds,  and  other  data  regarding  its  capa- 


320 


TOOLS  AND  PATTERNS 


eify.  But  it  will  be  fomid  that  in  a  large  faetory 
detaik  of  this  Mud  are  of  the  greatest  importance. 
For  work  of  this  sort,  then,  the  progressive  engineer 
in  a  large  factory  endeavors  to  make  his  index  of 
machine  tools  as  complete  as  possible.  I  have  found 
in  my  own  work  of  tool  engineering,  that  a  large 
card  with  an  outline  of  the  machine  tools  upon  it, 
in  at  least  two  views,  and  with  various  data  con- 
cerning feeds,  speeds,  and  capacity,*  is  of  the  great- 
est valne.  I  believe  that  a  card  is  much  better  than 
a  loose-leaf  book,  because  the  card  can  be  taken  out 
of  the  file  and  used  as  a  reference  by  the  tool  de- 
signer without  disturbing  other  data  which  may  apply 
to  other  machines. 

Perhaps  a  still  better  scheme  would  be  to  have  the 
data  on  the  various  machines  drawn  up  in  such  form 
that  it  can  be  blue*printed.  It  is  apparent  that  if  a 
blue-print  were  to  be  made  there  would  be  little 
danger  of  any  cards  getting  lost  and  of  the  conse- 
quent large  amount  of  labor  to  accumulate  the  in- 
formation <mee  more.  An  example  of  a  machine-tool 
record  record  card  which  I  have  found  of  great  valne, 
is  shown  in  Figure  134.  It  will  be  seen  that  this 
card  is  very  complete  with  respect  to  the  data  needed 
by  a  tool  engineer  to  determine  whether  or  not  a 
certain  type  of  machine  is  suited  to  the  work  in  hand. 
If  this  kind  of  information  is  lacking,  it  is  necessar}', 
in  designing  a  set  of  tools  for  any  given  machine,  to 
have  the  tool  designer  or  a  draftsman  go  into  the 
shop  and  make  certain  measurements  on  the  machine 
itself,  or  else  obtain  what  meager  information  he  can 
from  a  catalogue. 


PLANNING  AND  LAYING  OUT  WORK 


321 


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322 


TOOLS  AND  PATTERNS 


Now,  assuming  that  our  tool  en-ineer  is  well 
equipped  with  data  of  this  kind,  he  can  very  easily 
look  over  the  work  which  is  to  be  done  and  determine 
which  machine  of  a  certain  class  is  best  suited  to 
the  work.  He  may  be  aided  in  this  selection  by  a 
knowledge  of  the  way  in  which  a  piece  of  similar 
character  was  machined  at  some  previous  time,  but 
whether  this  is  the  case  or  not,  new  machine  tools 
may  have  been  added  since  that  time  which  are  more 
adaptable  to  the  work.  In  this  case  it  is  natural 
to  assume  that  the  tool  engineer  will  select  the  more 
modem  type  of  machine.  Another  point  which  must 
be  considered  in  the  same  connection,  is  the  location 
of  any  given  machine  in  the  factory.  The  matter  of 
handling  a  piece  and  taking  it  from  one  department 
to  another  and  then  back  again,  entails  an  extra 
cost  of  handling  the  work,  and  this  should  be  avoided 
as  far  as  possible. 

4:  Jigs,  Fixtures,  Tools,  and  Gauges.— Now,  the 
tool  engineer  has  reached  the  point  in  his  analysis 
at  which  he  is  ready  to  take  the  fourth  step.  The 
engineer  then  looks  over  the  blue-prints  carefully, 
and  notes  on  his  memorandum  sheet  that  he  needs 
the  following  tools:  a  driU  jig,  for  drilling  a  certain 
series  of  holes;  a  milling  fixture,  for  milling  a  cer- 
tain part  of  the  work ;  and  some  turret  lathe  fixtures, 
for  operations  of  a  cylindrical  character,  such  as 
boring  or  turning  of  the  work.  He  may  also  decide 
that  some  particular  piece  of  work  can  be  handled 
to  advantage  on  an  engine  lathe,  or,  if  it  is  large, 
on  a  vertical  boring  mill.  When  the  engineer  looks 
over  these  pieces  he  does  not  stop  to  consider  design, 


PLANNING  AND  «MM»  OUT  WORK 


323 


but  simply  decides  that  he  needs  one  jig  or  two  jigs 
and  ope  or  two  milling  fixtures,  and  perhaps  a  turret 
lathe  faceplate,  or  special  sub-jaws,  or  some  other 
types  of  fixtures.  At  this  time,  also,  the  matter 
of  gauging  is  considered,  and  a  memorandum  is  made 
as  to  the  types  of  gauges  needed— whether  they  are 
to  be  plug,  ring,  snap,  or  indicating.  Also,  whether 
the  work  is  to  be  from  some  of  the  rough 

surfaces  in  order  to  make  sure  that  a  proper  amount 
of  finish  is  left  for  some  subsequent  operation,  or 
to  make  sure  that  there  is  a  clearance  between  some 
finished  portion  of  another  part  and  a  rough  portion 
of  the  work  in  hand.  In  connection  with  this  phase, 
he  must  frequently  refer  to  the  assembly  drawing 
of  the  mechanism  in  order  to  make  sure  that  all 
these  points  have  been  considered.  Having  gone  to 
this  point  in  the  analysis,  the  tool  engineer  ,  is  now 
ready  to  go  into  the  matter  of  the  operations  on  the 
work  in  detail. 

5:  Laying  Out  Opemtian  Sheete.— In  connection 
with  the  preliminary  work  mentioned,  this  fifth  step 
represents  the  most  important  of  all  the  work  done 
by  the  tool  engineer.  One  of  the  peculiar  things 
about  the  average  manufacturer  is  that  when  he  sees 
an  operation  sheet  completely  and  properly  made  out, 
he  does  not  realize  for  an  instant  the  amount  of  work 
necessary  to  produce  a  result  such  as  that  which 
appears  on  the  operation  sheet.  He  sees,  for  example, 
a  sheet  perhaps  10  x  12  inches  in  size,  on  which  is 
a  list  of  the  operations  and  the  tool  called  for,  and 
everything  appears  to  him  to  be  as  simple  as  a,  b,  c. 
K  however,  the  executive,  in  considering  the  work 


324 


TOOIiS  AND  PATTERNS 


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PLANNING  AND  LAYING  OUT  WORK  325 


of  the  tool  engineer  in  this  respect,  were  to  stop  for 
a  moment  and  think  that  every  word  written  on  the 
sheet  represents  the  most  careful  tiiight,  and  that 
only  as  a  result  of  a  number  of  years  of  hard  ex- 
perience has  the  tool  engineer  acquired  the  knowledge 
and  skill  necessary  in  the  laying  out  of  an  operation 
sheet — ^then  the  executive  would  acquire  a  more 
wholesome  respect  for  the  tool  engineer  and  for  his 
work.   It  is  only  recently,  as  I  have  said,  that  the 
executive  has  been  abk  to  see  the  value  of  prelimi- 
nary planning  as  carried  out  and  brought  to  com- 
pletion by  the  experienced  tool  engineer.  Therefore, 
to  the  executive  who  has  not  reached  this  point,  and 
who  still  seems  to  consider  that  this  work  is  more 
or  less  of  a  **cut  and  dried"  proposition,  I  would 
recommend  that  he  reconsider  his  attitude  in  this  re- 
gard and  give  the  tool  engineer  the  credit  to  which 
he  is  entitled. 

In  the  first  place,  an  operation  sheet  in  itself 
should  be  made  in  such  form  that  it  gives  all  the 
information  necessary  in  regard  to  the  tool  equip- 
ment and  the  machines  necessary  to  do  the  work. 
I  have  laid  out  a  number  of  operation  sheets  for 
different  firms  and  on  various  classes  of  work,  and 
I  have  found  that  a  sheet  similar  to  the  one  illus- 
trated in  Figure  135  is  about  as  complete  as  any- 
thing of  this  kind  can  be  made  if  the  sheet  is  to  be 
of  a  size  to  allow  of  binding  in  a  loose-leaf  holder, 
for  ready  reference.  The  form  indicated  is  preferably 
about  14x17  inches  in  size,  but  it  can  be  made  a 
tnfle  smaller  if  desired.  It  is  bad  practice,  how- 
ler, to  endeavor  to  make  a  sheet  of  this  kind  very 


326        ,        TOOLS  AND  PATTERNS 


small,  as  the  necessary  infonnatioB  cannot  be  in- 
cluded on  a  sheet  of  mnch  smaller  size  than  that 
just  mentioned.  Referring  to  the  sheet  shown  in  the 
illustration,  the  reader  will  see  that  the  data  con- 
tained  on  it  is  complete  to  the  smallest  detail.  At 
the  upper  left  hand  comer  a  small  scale  drawing 
of  the  piece  appears,  in  order  that  a  reference  to 
the  various  operations  may  be  made  by  means  of 
letters,  as  indicated.  Generally  the  drawing  of  the 
piece  can  he  made  about  one-quarter  scale,  but  on 
very  large  work  it  may  be  advisable  to  leave  a 
larger  space  for  the  outline  drawing.  This  matter 
is  largely  determined  by  the  class  of  work  which  is 
to  be  done.  I  believe  that  the  form  shown  gives  every 
essential  detail  in  regard  to  any  piece  of  work  which 
is  to  be  manufactured,  and  forms  a  complete  record 
>  which  can  be  referred  to  at  a  moment's  notice.  If 
desired,  the  operation  sheet  can  be  printed  on  tracing 
paper,  and  afterward  blue-printed  so  that  any  num- 
ber of  record  proofs  can  be  made. 

It  will  be  seen  that  a  reference  to  a  sheet  of  this 
kind  will  give  the  executive  or  the  tool  engineer 
all  the  information  which  he  needs,  from  the  process 
used  in  manufacturing  the  product,  down  to  and  in- 
cluding the  type  of  gauge  needed  and  the  drawing 
number  of  the  gauge,  or  of  the  tool,  jig,  or  fixture.  In 
addition  to  this,  the  estimated  hourly  production  per 
machine  is  given  in  the  ''Remarks"  column,  and  the 
number  of  machines  which  are  required  for  what- 
ever production  may  be  determined  upon  before- 
hand. The  "Remarks"  column  also  has  a  little 
additional  space,  which  can  be  used  for  any  data 


PljANNINe  ANB  LAYINO  OUT  WOEK 


327 


in  addition  to  that  for  which  space  is  provided  in 
the  tabulated  list. 

After  the  tool  engineer  has  gone  into  the  matter  of 
machining  the  work,  and  has  laid  out  the  operations, 
the  tool  designers  use  these  sheets  to  work  from, 
and  as  fast  as  the  drawing  numbers  have  been  ob- 
tained from  the  clerk,  they  are  entered  up  in  their 
proper  place  against  the  tool  or  fixture  which  they 
represent — ^so  that  before  very  long,  the  record  is 
complete.  When  this  point  has  been  reached,  the 
sheet  should  -be  either  blue-printed  or  copied,  and 
an  original  should  be  filed  away  in  a  record  book, 
from  which  no  sheet  must  ever  be  taken  for  any  pur- 
pose whatsoever.  If  it  is  found  necesary  at  any 
time,  during  the  progress  of  the  work,  to  make  a 
change  in  the  method  of  handling,  a  record  of  the 
change  which  is  to  be  made  should  be  filed  in  a 
separate  book  devoted  entirely  to  this  purpose.  A 
statement  of  the  reasons  for  the  change  should  be 
embodied  in  the  record,  and  the  authority  for  making 
the  change  must  also  be  given.  It  is  not  an  uncom- 
mon thing  for  an  operation  sheet  for  a  difficult  piece 
of  work — like  a  crank  case  for  an  automobile,  or  a 
receiver  for  a  military  rifle — ^to  be  worth  several 
hundred  dolars  in  actual  labor  expended  on  the  plan- 
ning of  the  operations  shown  on  the  sheet.  It  is 
therefore  evident  that  it  behooves  any  factory  execu- 
tive to  see  that  the  greatest  care  is  taken  in  regard 
to  these  points. 

In  laying  out  the  operation,  the  tool  engineer  goes 
into  every  detail  of  manufacture  carefully,  as  will 
be  seen  if  the  illustration  is  referred  to.    At  the 


328 


TOOLS  AND  PATTERNS 


/*'■  Tu/HterfAce 


Sizm  -  O 


I'ftn  Chuck  - 1  /ieq  Dira.  /to  Mode  by  PMJ 
I-  Rouqh  Taming  Tool  /  Rftf  Std 

4-  Radi'us  Tool  ■  l  lfe<j.  Std. 

5-  False  Jaw  •  5  f>eq  Di^-N^  HH 

7-  Rough  Boring  Tool-  I  fftq  l>¥fM0>t9 
S- Finish  Boring  Tool-  I  RtQ-DwaMltOi 
3-Sizinq  Bar-  l-Req  Dwg.fh.  ISiO 
Kh  Sizing  Tool  ■  '-^eq  Dr»g  Ma  Ii20 
Ih  Rough  Facing  Tool  - 1  Req  Std. 
a-  Holder-  ?  Req  Sid.  for  2A  -HkJS.  J.L 
rS  Fixlure  for  Drilling  ■I  Re^Omif.mia 
H-  Drill  •  i  Req  20 Dia 
is-  Jig  for  Cenfenng  ■  I- Req.  Dwg.  HOi  W 


BLANK 

MOTOR  COMPANY 

TOOL  LAYOUT  FOR  PISTON 
li"^  To  6'"  OPERATIONS 

OukrBv  ho 

166-1-6 

scMx  r<i-o- 

L-79 

fll}.m    TOOL  IJkYCHJT  SHllT  W»  PI81X>N--€™ 


PLANNINa  AND  LAYING  OUT  WOBK  329 


tiinTM  O^mATiOM 


CLCVtHTM  OfrltATIOI* 

1-  Rough  OoasSMt  Block-  hHtq.  Dig.  Ak  OH  ^-"^  ■  ^ 

2-  Rouqh  Ortoiing  fyol-3-Ht^  Dtn.  Me  /37S 
J-  Knish  Turning  T99I  •  l-Rwg.  SM 

4-  fmisM  lUonts  taol  -  i-»ig.  Omf.ma» 

5-  Omrtmad  Turr»t  AHoOt-  Std  Ar  *4  lint  MX 

6-  Turmng  Stem  -  sid.  for  '4  Unh.  MTi  A 
1-Cenlmr-  I  Rtq  D»ig.Mo.l3n 

i-  Dram  Bock  Chuck-  IRt<i.  Ding  Ata  liJS 
9-  Finish  Crooving  Tool  - 1  fftif.  Dmg.  Ho.  liJS 
JO-  Forming  Tool  ■  I  Reg.  Dug  Ho.  IITS 
Ih  Chamfering  Tool-  /  Reg.  Dmg.  Ma  IS75 
It-  Oil  6rooring  Tool  •  l-Reg.  Dwg.  Ho.  OTS 
a- Fmsh  Cross  Slide  Block 'I- Reg  OmM^OM 
M-  Center  Bushing  -  /-  Reg.  0»g.  He  ISIS 

15-  J,g  for  Boring  -  l-Heg.  Dmq.H».  lit 

16-  Rough  Boring  Bar-  l-Ihg.  Vwg.  Ho  9H 
n-  Finish  Boring  Bar- l-Heg  Dmg. Ha  9M 
M-Remimr-l-mq.  OmRoSM 

I9-  Jig  Mr  iMiitf  • /-mfg.  Dmig.  He  tSt 

»  Drill-  IRHa.  flhOm 

21-  Jig  for  tMUmf-hRea.  AMt«t  AMT 

n  Drill.  i.Reg.  IS'JSmOm 

?S  Arhor  Plug  -  i-Heg.  'Am  Me.  ilt 

it  - Hand  Reamer  •  l-Reg.  Dmg.  He  lt» 


BLMNK  MORWCOMPMIV 


toot  LAYOOT  TOR  PISTON  7»" 
To  12"*  OPERATIONS 


Scale  S«l^'!oil 


|L'80 


iPSEATIOHS  7  TO  12 


TOOLS  AND  PATTERNS 


same  time,  however,  he  takes  up  points  in  connec- 
tion with  the  mannfacture,  and  makes  sketches  to 
give  the  tool  designer  his  ideas  concerning  tjie  fix- 
tures  which  must  be  made.  These  points  are  men- 
tioned  in  connection  with  the  sixth  point,  follow- 
ing, but  really  the  sketches  are  made  directly  in  con- 
nection with  the  laying  out  of  the  operation  sheet. 

6:  Free-Hand  Sketches.— The  matter  of  making  a 
sketch,  preliminary  to  the  designing  of  a  tool  or  fix- 
ture, is  of  considerable  importance,  and  the  progres- 
sive tool  engineer  is  systematic  in  this  as  in  other 
respects.  Therefore,  when  he  makes  a  sketch  for  a 
piece  of  work,  he  does  one  of  two  things:  he  either 
makes  the  sketch  on  a  looserleaf  pad  and  hinds  the 
sketch  in  a  book  kept  for  that  purpose,  in  numerical 
order  according  to  the  piece  number  assigned 
to  the  work;  or  he  attaches  a  sheet  of  sketches 
to  the  operation  sheet.  This  latter  method  is  not 
good,  for  the  reason  that  these  sheets  can  be  easily 
lost,  and  may  never  be  found.  In  which  event, 
the  tool  engineer's  ideas  may,  or  may  not,  be  fol- 
lowed—there is  no  proof,  in  either  case.  It  is  a  very 
simple  matter  to  have  a  number  of  books,  or  even 
a  note-book  of  plain  paper,  in  which  sketches  can  be 
kept  The  loose-leaf  system,  however,  is  much  to  be 
preferred,  since,  when  that  is  used,  the  arrangement 
of  the  pieces  in  numerical  order  can  be  more  easily 
kept. 

7:  Tiftlriwg  Layrat  SbeelB.— The  making  of  the  lay- 
out sheets  may  he  considered  by  the  executive  as  a 
costly  and  unnecessary  proposition,  yet  it  will  be 
found  that  in  the  long  run  the  preparation  of  these 


PLANNING  AND  LAYING  OUT  WORK  331 


sheets  will  save  much  time  and  expense.  A  lay- 
out sheet  like  that  shown  in  Figures  136  and  137  is  a 
picture  of  the  various  methods  used  in  handling  the 
work.  The  tools  which  are  to  be  used  in  the  work  are 
indicated  and  are  given  a  number,  and  anything  of  a 
special  nature  in  the  line  of  equipment  is  shown  in 
sufficient  detail  to  make  the  method  used  perfectly 
clear.  These  tool-layout  sheets  either  may  be  made 
in  connection  with  the  tools,  jigs,  and  fixtures  which 
are  being  drawn  up,  or  they  may  be  made  in  ad- 
vance. If  made  in  advance  of  the  actual  designing 
of  the  tools,  it  is  necessary  that  the  work  should  be 
done  by  a  man  of  wide  experience — one  who  pos- 
sesses the  knack  of  sketching  out  an  idea  rapidly. 
Layout  sheets  of  this  kind  are  usually  made  one- 
quarter  size,  and  the  sheets  may  be  so  proportioned 
that  they  can  be  reproduced  by  a  photostatic  process 
and  kept  as  a  record  with  the  operation  sheets;  or 
they  may  be  bound  in  a  separate  book  and  kept  for 
record.  It  will  be  noted,  with  respect  to  the  sheets 
shown  in  Figures  136  and  137,  that  a  complete  rec- 
ord of  tools  used  in  the  various  operations  is  given 
at  the  bottom  of  each  sheet,  and  that  the  drawing 
numbers  used  on  each  jig,  fixture,  or  tool  are  specified 
in  connection  with  this  work. 

It  is  unnecessary,  in  making  a  layout  sheet,  to  go 
into  the  smallest  detail  in  regard  to  the  design,  but 
an  effort  should  be  made  to  represent  a  fixture  which 

can  be  readily  understood,  and  which   M 

sufficient  detail  to  show  the  methods  used.  One  of 
the  greatest  advantages  in  a  tool-layout  sheet  is  in 
connection  with  turret-lathe  operations.  In  the  set- 


m  TOOLS  AND  PATTERNS 

tisig  up  of  a  turret  lathe  there  are  cases  when  an 
interference  appears,  and,  nnless  a  layout  of  some 
kind  is  made,  this  interference  may  not  be  noticed 
until  the  work  is  set  up  in  the  factory  and  the 
operator  is  ready  to  begin  the  work.  When  an  inter- 
ference is  not  discovered  until  as  late  as  this,  it  may 
cause  a  delay  of  several  days  in  the  production, 
and  this  delay  may  be  a  costly  one  to  the  manu- 
facturer. Looking  at  the  matter  from  all  stand- 
points, I  believe  that  for  work  requiring  a  number  of 
different  operations,  and  for  pieces  of  unusual  char- 
acter, the  use  of  a  layout  sheet  is  of  great  value. 
For  small  work  which  does  not  require  anything 
elaborate  in  the  line  of  special  tooling,  it  may  not 
be  necessary  to  make  such  a  layout,  but  even  in 
cases  of  this  kind  the  amount  of  labor  involved  is 
offset  by  the  advantages  gained. 

8:  Time4Study  Sheela.— There  are  two  ways  to 
make  a  time-study.  One  of  these  is  to  estimate  the 
amount  of  time  necessary  to  produce  the  work  at 
certain  speeds  and  feeds;  the  other  is  to  take  the 
actual  time  of  the  work  in  the  factory.  In  the  first 
instance,  the  man  who  makes  the  time-study  must 
be  a  man  of  broad  experience  who  is  familiar  with 
all  kinds  of  machine  tools,  and  one  who  has  access 
to  the  tables  giving  the  the  speeds  and  feeds  of 
which  various  machines  in  the  shop  are  capable.  In 
the  second  case,  it  is  unnecessary  to  have  a  man  of 
very  wide  experience,  because  he  simply  watches 
the  work  of  the  man  in  the  factory  and  notes  the 
amount  of  time  taken  for  doing  a  certain  piece  of 
work. 


PLANNING  AND  LAYING  OUT  WORK  333 


TIME  STUDY  SHEET  mmm^/M  

BLANK  MOTOR  CAR  CO.  HAME-^^  

DCTROrr.  IIICNI6MI.                   MAT.  —  £:.L  

OPN 

NO. 

DESCRIPTIOH 
OPEfUTldN 

tYPE  1 
MACHINE ' 

MTTIM6 
SPCEO 
fT.PCTHm 

DIAM.  1 

or 

WORK 

OF 
WORK 

MIOTH 

OF 
SURFACE 

R.R  M.  ' 
OR 

-ECDPOK 

Rev. 

OR 

EUTTM6 
TIMe 
MIN. 

TOTAL 

2 

Rough  Turn  A 

^ZRRkJ 

SO 

f05% 

130 

48 

0.040 

zt 

2k 

Rouqh/fedius  C 

m 

m 

* 

t 

m 

Attow  Br  S9t  on^fwiowng 

work 

3 

R.&F.  Borw  fD> 

SO 

96'%7 

I5%f 

48 

0.O4O 

Size  <D) 

m 

m 

S 

48 

a  040 

Face  i£KC.5> 

* 

* 

t 

*■ 

t 

* 

*  1 

Attow  fyr  5»/  tf/r  m*el  nmonnq  work,  indrxf 

r*q  etc. 

/4 

4 

so 

2S0 

0005 

2 

Altmr  iSfr  st^u^ontl  rmnovmg  wwrk.  ckemtmgi 

Jig  9 

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1 

3 

6 

Center  End  (C> 

Sens  Dr. 

so 

12 

500 

i 

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7 

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V  MS. 

50 

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48 

0.040 

Rough  6nored<A> 

— 

40 

m 

6% 

36 

0.006 

1 

Finish      •  tB) 

m 

50 

m 

6% 

fi 

0.006 

Form  ffod.  fO 

• 

30 

m 

1% 

28 

Hand 

1 

2 

Aiiotv  for  setting  ami removirtg,  indexing  andgoging 

2 

8 

Rough  Bore  <F> 

Co/bum 

50 

22%, 

58% 

250 

0.010 

/ 

'4 

Finish  Bore  <  F> 

» 

SO 

« 

m 

m 

»• 

/ 

Ream        f  /\> 

m 

30 

m 

ISO 

Horul 

i 

Altow  for  rwnomng  and  iftaerfing  foo/s  am 

i  work 

2 

S 

9 

Pri//  <J> 

SensDr 

SO 

sm 

i 

I 

Allow  for  rtm^vmg  €m 

i  inserting » 

rork 

>4  \'i 

9A 

Drill  12  Holes  <  H> 

SensDe 

60 

ts% 

exiz 

4000 

Hand 

ti 

Al/0¥f  for  indexing,  S^ffirrg  and  ren 

)<?yin 

9 

li 

3 

K> 

Orind  Q.a  (A) 

Norton 

4000 

13 

0 

900 

oooos 
meoi 

s 

Allow  for  wMngmtdremomtg  work,  gaging  etc. 

6 

II 

^Benck 

mm 

kdnd 

fi 

no.  138.    TIME-STUDY  SHEET  ON  A  QJS&T-JSm  Vmm 


TOOLS  AND  PATTERNS 


It  is  entirely  possible  for  an  experienced  man  to 
determine  very  closely  the  mnpunt  of  time  which 
will  be  required  for  the  performance  of  a  given 
operation  on  any  piece  of  work.  His  experience  will 
tell  him  approximately  what  feed  and  speed  can  be 
safely  used  on  the  work,  and  as  he  can  easily  ascer- 
tain the  length  of  the  surface  which  he  is  about  to 
cut,  the  time  can  be  quickly  estimated.  A  very  good 
illustration  of  a  time-study  sheet  is  shown  in  Figure 
138;  it  will  be  noted  that  various  columns  are  pro- 
yided  for  the  different  data  used  in  connection  with 
the  estimates.  The  time-study  sheet  itself  is  self- 
explanatory. 

Now  let  us  take  up  the  method  of  figuring— :or  per- 
haps we  should  say  estimating — ^the  amount  of  time 
for  a  given  piece  of  work,  as  indicated  by  the  layout 
sheet.  If  the  tool  engineer  is  about  to  figure  the 
time  necessary  on  the  work,  his  first  step  is  to  deter- 
mine the  rate  and  settle  the  matter  of  cost  of  the 
tool.  The  best  method  of  holding  the  work  must  al- 
ways be  determined,  and  also  the  points  from  which 
the  piece  is  to  be  located.  Other  matters  in  connec- 
tion with  the  design  of  tools  and  fixtures  have  been 
taken  up  in  the  previous  chapters. 

9:  Machine  Tools  Required. — ^After  the  time-study 
sheet,  mentioned  previously,  has  been  made,  the 
amount  of  time  necessary  with  each  machine  can  be 
easily  determined,  and  in  order  to  make  sure  that  a 
sufficient  number  of  machine  tools  are  at  hand  to 
give  the  production  necessary,  and  within  the  proper 
time,  a  record  must  be  kept  to  show  how  many 
pieces  are  to  be  handled  by  any  one  type  of  machine, 


PLANNING  AND  LAYING  OUT  WOEK  335 

and  how  much  of  this  machine  time  will  be  needed. 
The  best  way  to  determine  whether  the  requisite 
number  of  machines  is  available,  is  to  make  a  tabu- 
lated list  of  the  various  machines  in  the  factory, 
and  after  the  time-study  sheet  has  been  mde,  the 
amount  of  time  which  each  piece  consumes  on  a 
given  type  of  machine  can  be  tabulated  in  the  Ust 
mentioned.  In  this  way,  as  the  work  of  the  tool 
engineer  progresses,  it  is  very  easy  to  see  when 
any  one  machine  or  type  of  machine  is  overloaded. 
Then,  when  it  is  found  that  a  certain  type  of  ma- 
chine has  more  of  a  burden  than  it  can  reasonably 
be  expected  to  sustain,  some  of  the  work  which  has 
been  placed  upon  it  can  be  transferred  to  some  other 
type  of  machine  adapted  to  the  work.  By  using  a 
process  of  this  kind,  and  by  carrying  all  these  mat- 
ters along  together,  the  matter  of  distribution  of  the 
work  in  the  factory  can  be  adjusted  to  the  best  ad- 
vantage. The  last  point  can  now  be  taken  up  by 
the  tool  engineer. 

10:  Setting  Piece-Work  Prices.— The  matter  of  set- 
ting piece-work  prices  does  not  strictly  come  under 
the  head  of  the  tool  engineer's  work — the  time-study 
sheet  for  the  various  operations  on  each  piece  of  work 
is  used  by  the  cost  department  in  obtaining  a  basis 
upon  which  to  figure  the  cost  of  production.  If  the 
work  01.  the  time-study  sheet  has  been  carefully 
done,  the  piece-work  prices  can  be  determined  with 
great  accuracy  by  the  cost  department,  and  the  prices 
so  set  will  be  found  to  give  excellent  results.  If, 
after  a  test  has  been  made  of  the  production  time  as 
wwlicated  by  the  time-study  sheet,  there  is  found 


TOOLS  AND  PATTERNS 


to  be  a  considerable  difference  in  time,  then  the  mat- 
ter should  be  immediately  referred  to  the  tool  engi. 
Beer  for  Ms  attention.  If  it  should  be  found  that 
an  error  has  been  made  in  his  estimate  of  produc- 
tion, then  the  piece-work  price  may  be  changed  to 
allow  for  the  error  On  the  other  hand,  if  it  is  found 
that  the  workman  is  really  consuming  too  much  time 
in  doing  the  work,  the  matter  of  speeds  and  feeds 
which  he  is  using  should  be  carefully  looked  into, 
in  order  that  the  source  of  the  trouble  may  be  deter- 
mined. 

Often  I  have  found  that  the  only  reason  why  the 
production  time  did  not  check  with  the  time-study, 
was  that  the  operator  was  not  using  the  speeds  and 
feeds  whieh  would  produce  the  best  results.  There 
are,  of  course,  exceptional  cases  in  which  the  work 
is  of  such  a  nature  that  the  speeds  and  feeds  wliicli 
have  been  estimated  upon  cannot  be  used,  but  if  this 
eontingency  occurs  it  is  time  for  the  factory  super- 
intendent or  the  general  foreman  to  step  in  and  find 
out  why  the  castings  or  forgings  are  not  what  thsy 
diould  bOt 


CHAPTER  XXII 


ESTIMATING  COSTS 

Time  Factor  in  Estimating  Ck>sts. — The  problem  of 
estimating  costs  of  manufacturing  work  is  one  which 
is  of  interest  to  every  manufacturer.   In  some  eases 

a  small  factory  is  engaged  in  the  building  of  jigs, 
fixtures,  or  other  tools  for  outside  concerns,  and  in 
many  cases  the  firm  which  is  doing  the  work  is  com- 
pelled to  submit  a  bid  in  competition  with  other 
factories.  It  is  therefore  of  the  utmost  importance 
to  make  sure  that  the  bid  which  is  submitted  to  the 
customer,  is  such  that  it  stands  a  fair  chance  in  the 
competition  with  the  others.  In  order  to  make  sure 
that  the  prices  which  are  quoted  to  the  customer 
are  reasonable  and  proper,  and  at  the  same  time  that 
the  estimate  submitted  is  made  with  a  wide  enough 
margin  to  give  a  substantial  profit  to  the  manilic- 
turer,  a  careful  estimate  of  the  time  necessary  to 
produce  these  Tarious  pieces  which  are  to  be  made,  is 
a  very  important  factor. 

Broad  Experience  Necessary. — This  is  one  way  in 
which  the  estimating  of  costs  can  be  applied,  but 
there  are  other  applications  which  are  fully  as  im- 
portant. Let  it  be  supposed  that  a  manufacturing 
concern  is  about  to  submit  a  bid  for  up  a 

large  number  of  pieces  which  are  componelits  of  a 


338 


TOOLS  AND  PATTERNS 


military  fifle;  or  that  a  great  number  of  shrapnel 
shells  are  to  be  made,  and  that  the  bids  which  are 
to  be  submitted  are  in  competition  with  those  of 
numerous  other  manufacturers  who  are  looking  for 
the  same  work.  It  is  very  evident,  then,  both  that 
the  maniifaetiirer  who  intends  to  do  this  class  of 
work  should  be  well  prepared  as  regards  his  mechan- 
ical equipment  of  machine  tools  and  shop  tools,  and 
also  that  his  engineering- force  be  well  fitted  to  make 
estimates  of  production  and  of  the  costs  of  machui- 
ing.  In  the  first  place,  either  of  the  proiwsitions 
mentioned  requires  the  services  of  men  who  have  had 
long  experience  in  the  shop,  and  also  in  the  planning 
of  operations  for  work  which  is  to  foe  done  in  quan- 
tity. 

Let  us  take  the  case  of  the  factory  which  is  pre- 
pared to  build  jigs  and  fixtures.  It  is  much  more 
difficult  for  a  concern  of  this  kind  to  make  an  esti- 
mate on  the  cost  of  a  jig  or  fixture,  than  to  estimate 
the  production  which  can  be  obtained  for  certain 
pieces  of  work  which  are  being  put  through  the  fac- 
tory in  large  quantities.  In  the  case  of  the  manu- 
facturing of  jigs  or  fixtures,  the  work  must  be  re-set 
a  number  of  times  during  the  process  of  manufacture, 
and  every  precaution  must  be  taken  to  insure  accu- 
racy. All  these  operations  take  a  certain  amount  ot 
time,  the  exact  amount  depending  largely  upon  the 
skill  of  the  tool-maker.  It  is  therefore  difficult  to 
estimate  this  class  of  work  as  closely  as  the  other 
kind  mentioned. 

In  the  case  of  the  manufacturing  of  a  great  many 
parts  of  the  same  kind,  it  is  entirely  possible  for 


ESTIMATING  COSTS 


the  manufacturer  to  provide  means  of  holding  and 
locating  the  work  for  the  various  operations  which 
are  to  be  done  upon  it  in  such  a  way  that  the  parts 
will  come  to  the  desired  size  almost  automatically. 
It  is  a  matter  of  judgment.  Unless  the  man  who  is 
selected  for  making  estimates  of  this  kind  is  one  of 
broad  experience,  unless  he  has  had  a  number  of 
years  of  actual  shop  work,  together  with  considerable 
experience  in  the  actual  engineering  processes,  and 
unless  he  has  a  logical  mind,  he  is  very  likely  to 
make  a  complete  failure  of  estimating  the  cost  of 
work  which  is  to  be  done. 

Usual  Causes  of  Failure. — ^If  a  jig  or  a  fixture  is 
to  be  made  up,  and  there  is  a  drawing  from  which 
the  estimate  can  be  made,  the  estimator  can  proceed 
to  take  up  the  various  machining  operations  which 
are  necessary  to  complete  the  piece  of  work,  and  can 
jot  down  the  amount  of  time  which  he  thinks  it  would 
be  necessary  to  consume  for  the  various  operations, 
always  remembering  to  make-  due  allowance  for  the 
time  lost  by  the  tool-maker  in  looking  up  tools  and 
in  setting  up  the  work  preparatory  to  the  machin- 
ing. Allowance  must  also  be  made  for  careful 
measuring,  in  order  to  insure  proper  accuracy  in  the 
finished  product.  It  will  be  readily  seen  that  in 
order  to  do  this  kind  of  work  the  estimator  must  be 
a  man  who  has  actually  done  the  work  in  the  factory, 
in  order  that  he  may  know  exactly  how  a  nmn  would 
be  obliged  to  go  to  work  to  do  the  necessary  ma- 
chining. The  usual  causes  of  failure  in  estimating 
a  piece  of  work  such  m  that  mentioned,  are  that  . 
sufficient  allowances  are  not  made  for  the  setting 


340 


TOOLS  AND  PATTERNS 


up  and  the  getting  ready  to  go  to  work,  as  well  as 
for  time  which  the  man  consnmes  in  actually  making 
the  fixture. 

Secret  of  Estimating  Costs. — ^Briefly  stated,  the 
entire  secret  of  estimating  costs  of  production  lies 
in  allowii^  a  man  sufficient  time  to  do  the  work, 
remembering  at  the  same  time  that  there  are  little 
incidental  things  which  tend  to  increase  the  time 
neeessaiyy  because  of  a  failure  to  find  a  certain  tool 
that  is  wanted,  or  owing  to  difficulties  that  arise  when 
castings  or  forgings  are  not  made  in  exactly  the  right 
way.  All  these  points  must  be  taken  into  consid- 
eration by  the  estimator,  and  the  time  allowance  must 
be  made  on  an  hourly  basis.  The  amount  of  profit 
which  is  to  be  made  by  the  manufacturer  is  depend- 
ent, to  a  great  extent,  upon  the  overhead  expense 
in  the  factory.  There  are  many  other  items,  also, 
which  must  be  considered  in  making  up  an  estimate 
of  the  cost  of  production.  Among  them  are  the 
matter  of  the  cost  of  material.  In  some  cases  the 
jig  or  fixture  is  made  of  cast  iron,  and  the  pattern 
is  to  be  made  by  the  same  person  who  is  to  build 
the  fixtures.  In  a  case  of  this  kind,  it  is  obvious 
that  the  pattern-maker's  time  must  also  be  charged 
against  the  account.  Also,  the  amount  of  stock  and 
flie  weight  of  the  cast  iron  which  goes  to  make  up 
the  jig,  together  with  the  cost  of  the  iron  in  the 
jig,  must  be  taken  into  consideration. 

Skilled  and  UnsldllBd  LalNir.— Due  time  must  be 
allowed  for  the  hardening  of  any  parts  of  the  jigs  or 
fixtures  which  are  to  be  hardened,  and  it  must  also  be 
remembered  that  after  a  part  is  hardened,  it  is 


ESTIMATING  COSTS 


341 


usually  necessary  to  grind  it,  in  order  that  the  dis- 
tortion caused  by  the  hardening  process  may  be  re- 
moved and  the  piece  may  be  properly  fitted.  Of 
course  there  are  some  parts  which  may  be  hardened 
without  affecting  the  jig  or  fixture  in  its  vital  points 
in  the  proce8«-for  example,  snch  things  as  the 
heads  of  screws  or  their  points,  a  C- washer,  a  lever, 
or  some  other  part  of  minor  importance.  No  mat- 
ter how  small  the  piece  of  work  may  be,  however, 
it  must  be  considered  in  the  making  of  the  jig  or 
fixture,  and  if  there  are  a  number  of  pieces  of  the 
same  kind  (such  as  locating  pins  or  something  of 
similar  character),  several  of  these  pieces  can  be 
made  up  at  the  same  time  by  a  boy  or  an  apprentice, 
or  by  a  comparatively  inexperienced  man. 

This  being  the  case,  the  time  for  these  various 
pieces  need  not  be  charged  against  the  work  at  as 
high  a  rate  as  that  charged  for  some  of  the  actual 
tool-making.  As  a  matter  of  fact,  it  is  customary, 
in  factories  which  do  a  considerable  amount  of  this 
kind  of  work,  to  portion  out  such  parts  as  can  be 
made  by  an  inexperienced  man,  and  thus  obtain  the 
benefit  derived  from  a  cheaper  rate  of  labor.  In  cases 
of  this  kind,  the  man  who  roughs  out  the  part  leaves 
a  certain  amount  of  work  to  be  done  or  completed  by 
the  tool-maker,  doing  only  the  crudest  part  of  the 
work  himself. 

No  Hard  and  Fast  Rule. — There  can  be  no  definite 
rule  which  a  man  can  follow  in  estimating  costs  for 
work  of  this  character.  As  stated  before,  it  is  always 
necessary  to  make  a  generous  allowance  for  the  set- 
ting up  time  and  incidental  time  needed  by  the  work- 


342 


TOOLS  AND  PATTERNS 


men  in  obtaining  tools  from  the  tool  room,  and  in 
making  measnrements,  laying  ont  the  work,  and  so 
on.  Let  it  be  supposed  that  a  number  of  jigs  or 
fixtures  of  very  similar  character  are  to  be  made  by 
a  mannfaetnrer  for  an  outside  concern.  Then  the  esti- 
mator would  consider  that  these  various  planing  or 
shaping  operations  which  are  to  be  done  on  the  work, 
can  be  carried  along  at  the  same  time;  if  this  plan 
be  f ollowed,  a  considerable  saving  in  time  will  be 
effected. 

There  are  so  many  conditions  which  affect  the 
building  of  tools  of  this  type,  that  it  is  a  very 
difficult  matter  to  go  into  the  details  of  the  processes 
used  in  different  factories.  About  all  that  can  be 
said  in  this  regard  has  already  been  mentioned.  A 
specific  example  or  two  could  be  given,  but  they 
would  not  serve  any  valuable  purpose,  and  might  only 
confuse  the  reader.  However,  in  the  estimating  of 
costs  for  work  which  is  to  be  put  through  the  factory 
in  large  quantities,  other  factors  which  are  more  nearly 
stable  come  into  play. 

A  ManofaetaTing  Case. — Let  us  now  consider  the 
estimating  of  cost  for  a  manufacturing  proposition 
involving  a  number  of  pieces  of  a  similar  kind, 
which  are  to  be  made  up  entirely  on  an  automatie 
screw  machine.  Under  such  circumstances  it  is  a 
very  simple  matter  to  decide  exactly  which  are  the 
tools  that  must  be  used  for  the  work,  and  since 
the  material  from  which  the  work  is  to  be  made  is 
of  a  certain  character,  and,  furthermore,  since  the 
feeds  and  speeds  of  the  machine  can  be  easily  de- 
termined, it  is  evident  that  a  very  close  estimate  of 


ESTIMATING  COSTS 


343 


the  actual  tim^  needed  to  produce  the  work  can  be 
obtained  without  great  difficulty.  Let  us  assume 
further  that  the  job  includes  a  number  of  pieces  which 
must  be  machined  on  an  automatic  screw  machine,  that 
a  series  of  holes  must  be  drilled  in  each  piece,  and 
that  a  single  milling  operation  is  called  for.  It  will 
be  seen  that  although  this  piece  of  work  is  some- 
what more  difficult  to  figure  than  the  other  one  men- 
tioned, it  is  nevertheless,  a  simple  manufacturing 
proposition.  In  this  latter  case,  however,  it  is  neces- 
sary to  take  into  consideration  the  fact  that  certain 
tools  and  fixtures  must  be  made,  if  the  work  is  to  be 
done  properly  and  is  to  come  within  the  required 
limit.  A  jig  and  a  milling  fixture  will  both  be  neces- 
sary. The  cost  of  these  fixtures  must  be  estimated, 
and  the  price  must  be,  included  in  the  cost  which  is 
submitted  to  the  customer  for  whom  the  work  is  to 
be  done. 

Overhead  Expense.  Hourly  Basis,— The  matter  of 
overhead  expense  is  so  broad,  and  furthermore  it  is 
of  such  a  variable  character,  that  it  is  difficult  to 
give  anything  more  than  a  general  idea  of  it  in  this 
chapter.  Briefly,  the  overhead  expense  of  a  factory 
conskts  of  a  burden,  or  load,  over  and  above  the  ap- 
parent cost  of  labor.  That  is  to  say,  if  a  workman 
spends  one  hour  in  turning  out  a  piece  of  work  and 
if  his  rate  is  30  cents  an  hour,  this  burden  must  be 
added  to  the  workman's  actual  cost  of  labor,  in  order 
that  the  cost  of  equipment,  cost  of  power,  and  various 
other  costs,  may  be  taken  care  of  properly.  In  addi- 
tion to  these  matters,  the  manufacturer's  profit,  and 
the  dispreciation  of  his  machinery  and  equipment, 


TOOLS  AND  PATTERNS 


iniist  also  be  oonsideredi  together  with  the  percen- 
tage  on  the  investment,  in  order  that  when  the  work  is 
completed  there  may  be  a  large  enough  profit  to 
prove  to  the  manufacturer  that  his  business  is  a 
profitable  one.* 

It  is  evident  that  factories  of  different  kinds  and 
under  different  management  would  have  a  proportion 
of  overhead  expense  that  would  differ  according  to 
the  factory  conditions  and  many  other  items  pertain- 
ing to  ilie  management.  In  the  past  few  years  I 
have  noted  a  wide  difference  between  the  bids  sub- 
mitted by  different  manufacturers  on  the  same  jigs 
and  fixtures.  This  difference  in  prices  makes  it  clear 
that  either  there  is  %  tremendous  difference  in  the 
■  way  in  which  different  manufacturers  estimate  on  the 
same  piece  of  work,  or  else  the  equipment  which  these 
viyrious  manufacturers  use  for  producing  the  work 
is  in  some  cases  better  adapted  than  in  others  to  the 
class  of  work  on  which  these  prices  were  submitted. 

Different  Methods  but  One  Piinciple.--One  particu- 
lar inslanee  is  worthy  of  mention.  A  set  of  blue- 
prints of  a  group  of  three  indicating  gauges  was  sent 
to  five  different  manufacturers,  with  a  request  for 
bids.  The  lowest  bid  received  was  $670,  the  highest 
bid  was  $1472.  The  work  was  given  to  the  man 
whose  bid  was  tie  lowest,  and  the  work  produced  was 
of  so  high  an  order  that  it  passed  a  most  rigid  inspec- 
tion. It  is  evident  from  this  case  that  the  manu- 
facturer whose  bid  was  the  highest  would  have  been 


*  A  full  discussion  of  the  factors  affecting  the  determination  of 
burden  or  overhead  will  be  found  in  Industrial  CJost  Finding,  by  N.  T. 
Flcker.  Factory  Management  Ck)urse. 


ESTIMATING  COSTS 


345 


able  to  make  a  very  high  profit  on  the  work,  had  he 
succeeded  iu  obtainiug  the  coutract,  or  that  his 
operating  methods  were  very  inferior.  As  a  matter  of 
fact,  I  have  found  that  many  manufacturers  who  bid 
upon  this  class  of  work  do  not  go  to  the  trouble  of 
figuring  out  all  the  details  of  manufacture  carefully, 
but  merely  look  over  the  work  and  form  a  rough 
estimate  from  their  previous  knowledge  of  how  long 
it  takes  to  do  the  work.  To  be  sure,  a  man  of  wide 
experience  can,  even  by  this  method,  obtain  a  close 
approximation  of  the  time  necessary  to  produce  a 
given  piece  of  work,  always  provided  that  this  man 
has  had  experience  with  other  work  of  a  similar  kind. 
On  the  other  hand,  a  careful  estimator  who  has  had 
the  necesary  shop  experience  and  many  years  of 
actual  shop  training,  can  obtain  a  much  closer  ap- 
proximation of  the  cost  of  production  by  figuring  out 
the  actual  amount  of  work  which  must  be  done  to 
complete  the  piece. 

Evidently,  then,  different  processes  of  estimating 
cost  are  used  by  different  manufacturers.  It  is  hard 
to  say  just  what  method  is  best  suited  to  a  particu- 
lar class  of  work,  since  so  many  factors  enter  into 
the  matter.  It  is  always  safe,  however,  to  act  upon 
the  principle  that  the  careful  estimator  who  figures 
the  work  on  the  hourly  basis  will  obtain,  in  the  long 
ran,  a  much  more  uniform  and  satisfactory  estimate 
of  cost  than  the  man  who  depends  upon  snap  judg- 
ment. Each  manufacturer  must  be  a  law  unto  him- 
self in  this  regard,  but  the  careful  man,  who  adopts 
the  principle  of  safety  first,"  will  find  himself  better 
off  than  the  one  who  uses  the  **hit  or  miss"  method. 


CHAPTEB  XXin 


INTERNAL,  EXTERNAL  AND  THREAD  GAUGES 

Aeenraiqr  Beqnired  in  Intrndiangeable  Muiufac- 
tore. — When  a  number  of  parts  are  to  be  made  that 
will  be  interchangeable  one  with  another,  it  is  neces- 
sary to  make  the  parts  within  definite  limits  of  accu- 
racy. Before  going  into  this  subject  let  us  first  under- 
stand the  different  terms  which  apply  to  gauging  and 
gauging  systems.  Let  us  also  determine  the  use  of  a 
gauge  and  its  applications  to  the  work. 

In  the  first  place  in  assuming  that  a  number  of  pieces 
of  the  same  size  are  to  be  made,  it  will  be  necessary 
for  the  workman  to  measure  each  piece  as  he  is  pro- 

^  ducing  it  in  order  to  be  sure  that  the  sizes  are  kept 
to  the  dimensions,  unless  a  system  of  gauges  is 
made  for  the  work.  He  would  use  for  this  pur- 
pose a  set  of  micrometer  calipers  and  other  measuring 
instruments  of  precision  depending  upon  the  class  of 
work  on  which  he  was  engaged.  But  as  these  instru- 
ments are  all  capable  of  being  set  to  certain  sizes,  and 
are,  therefore,  flexible,  it  is  obvious  that  in  using  these 
tools  he  must  be  able  to  discriminate  in  their  applica- 
tion.  He  must  guard  against  error  in  reading  the 

Jis  micrometer,  or  other  instruments.  And,  again,  the 
continual  use  of  such  delicate  instruments  in  manu- 
facturing is  not  to  be  commended  on  account  of  the 

m 


iNTBlNAIi,  EXTERNAL  AND  THREAD  GAUGES  347 

wear  involved.  In  order,  then,  to  take  the  place  of 
these  delicate  instruments,  especial  gauges  can  be 
made  to  give  fixed  readings;  also  in  order  to  provide 
for  slight  variations  in  the  work,  *Mimit"  gauges  can 
be  used. 

Let  it  be  supposed  that  automobiles  are  to  be  made 
up  in  large  quantities  complete  in  every  part  and  on 
an  interchangeable  basis,  such  that  one  part  if  injured 
or  worn  out  can  be  replaced  by  another  which  will  be 
the  counterpart  of  the  previously  used  portion. 
Assuming  that  a  condition  of  this  kind  is  found,  the 
first  step  in  the  gauging  system  must  be  a  determina- 
tion of  the  different  kinds  of  fits  which  will  be  used  in 
the  different  parts  of  the  automobile.  In  this  connec- 
tion the  quality  of  the  product  must  be  taken  into  con- 
sideration. That  is  to  say,  if  an  excellent  machine  is 
to  be  manufactured,  the  workmanship  will  be  natu- 
rally of  a  high  grade  and,  therefore,  the  allowances  for 
the  various  fits  must  be  consistent  with  the  quality  of 
the  machine  to  be  manufactured.  Let  us  consider  this 
matter  in  detail  under  the  various  headings  given  here- 
with. 

Terminology. — ^When  two  parts  are  to  be  fitted  to- 
gether the  relation  of  these  parts  to  each  other  is  in 
the  nature  of  a  fit  of  some  kind.  For  example  when  a 
shaft  is  to  be  fitted  to  a  bearing  in  such  a  way  that  it 
will  revolve  freely  in  the  bearing,  the  fit  will  be  called 
a  running  fit".  A  *'push  fit"  is  somewhat  closer  than 
a  running  fit;  the  parts  are  not  free  to  revolve,  but  can 
be  assembled  by  hand  without  using  much  pressure.  A 
''drive  fit"  is  such  that  the  parts  can  be  assembled  only 
by  means  of  pressure  under  an  arbor  press  or  by  dri^' 


348 


TOOLS  AND  PATTERNS 


ing  with  a  hammer.  A  "force  fit*'  is  such  that  the 
parts  must  be  assembled  by  means  of  teat  and  hydrau- 
lic pressure. 

It  is  evident  that  there  may  be  several  kinds  of  run- 
ning fits;  that  is,  there  may  be  several  grades  of  these 
fits.  If  we  should  assume  that  a  farm  machine,  such  as 
a  harvester  or  mowing  machine,  was  to  be  made,  it 
would  be  apparent  that  such  a  machine  subjected  as  it 
is  to  heavy  usage  and  in  the  hands  of  men  who  are  not 
mechanical,  w^ould  need  to  be  rather  freely  put  together. 
This  class  of  fit  would  obviously  be  less  accurate  than 
if  the  machine  in  question  were  to  be  an  automobile  or 
a  sewing  machine  or  some  other  type  of  mechanism 
requiring  careful  workmanship.  Therefore  it  is  plain 
that  several  grades  of  running  fits  must  be  made  to  suit 
different  kinds  of  work.  These  matters  are  entirely 
dependent  upon  manufacturing  conditions  and  also  the 
requirements  of  the  mechanism  after  it  is  completed. 

Manufacturing  conditions  are  such  that  it  is  easier 
to  make  shafts  or  studs  to  a  size  a  little  under  or  a  lit- 
tle over  a  specified  dimension  than  it  is  to  make  a  hole 
over  or  under  a  given  size.  This  is  due  to  the  fact  that 
a  hole  is  usually  drilled,  bored,  reamed,  or  ground.  It 
is  not  a  very  easy  matter  to  make  a  reamer  so  that  it 
will  •cut  a  hole  much  different  from  the  standard  size 
(although  a  new  reamer  is  inclined  to  cut  a  trifle  over- 
size, and  after  it  is  worn  a  little  it  may  cut  a  little 
under-«ize).  Therefore  the  size  of  the  holes  are  usually 
kept  as  nearly  to  a  standard  as  the*  uses  of  tools  will 
permit.  As  a  general  thing  it  is  not  customary  to  put 
any  kind  of  a  limit  on  a  hole  which  is  to  be  drilled,  but 
holes  which  are  to  be  reamed  or  ground  can  be 


INTERNAL,  EXTERNAL  AND  THREAD  GAUGES  349 

machined  within  close  limits  of  accuracy.  It  is  well  to 
state  parenthetically  at  this  point  that  as  the  hole  is 
usually  made  as  nearly  standard  as  possible  the  limits 
of  accuracy  within  which  it  must  be  machined  are  de- 
termined by  conditions.  The  shafts  or  studs,  however, 
which  fit  the  holes  are  made  within  limits  determined 
by  the  class  of  fit  for  which  they  are  intended. 

Terms  Used  in  Oangiiif . — In  mentioning  the  terms 
used  to  describe  various  points  in  connection  with 
gauging,  there  are  three  words  the  meaning  of  which 
are  not  always  clear  to  the  average  man.  These  termis 
are  "allowance,''  "tolerance,"  and  "limit." 

The  term  allowance  is  used  to  describe  the  relation 
that  one  piece  bears  to  another  when  the  two  parts  are 
assembled.  For  example,  if  a  shaft  were  to  be  fitted 
into  a  hole  so  as  to  revolve  freely,  it  would  be  neces- 
sary to  make  an  allowance  between  the  size  of  the  hole 
and  the  size  of  the  shaft  so  that  the  right  relation  will 
be  maintained  between  the  two  surfaces  and  permit  the 
shaft  to  revolve  with  the  proper  amount  of  clearance 
and  sufficient  freedom  in  the  hole.  If  a  hole  were  to 
be  reamed  to  1  inch  in  diameter  and  a  shaft  were  to  be 
revolved  in  this  hole,  we  can  assume  that  an  allowance 
of  0.001  inch  must  be  made  on  the  shaft  under  the  size 
of  the  hole  so  as  to  permit  free  turning.  It  will  be 
seen  that  the  kind  of  fit  which  must  be  obtained  be- 
tween two  pieces  of  work  determines  the  possible  al- 
lowance. 

The  term  tolerance  applies  to  the  total  amount  of 
variation  permissible  in  manufacturing  any  given  piece 
of  work.  As  an  example,  let  us  take  a  shaft  1  inch 
^  diameter  which  must  be  machined  to  a  given  size. 


350 


TOOLS  AND  PATTERNS 


Tolerance  is  determined  by  the  machining  possibilities 
and  the  quality  of  fit  which  is  to  be  made.  If  it  is  sup- 
posed that  the  shaft  is  to  be  machined  within  a  toler- 
ance of  0.0005  inch,  then  the  maximnm  and  minimum 
variations  must  not  differ  by  more  than  the  amount 
mentioned. 

The  term  limit  is  applied  to  the  maximum  and  muii- 
mum  size  of  work  to  be  produced  as  determined  by  the 
tolerance.   For  example,  if  the  work  is  to  be  made 


FIO.  139.    DIAGRAM  SHOWINa  APPLICATION  OP  LIMITS  TO  A 

8HAPT  AND  HOLE 


within  a  tolerance  of  0.0005,  then  the  limits  within 
which  the  piece  may  be  permitted  to  vary  must  be  such 
that  their  total  amount  will  not  exceed  the  prescribed 
tolerance. 

Let  us  take  a  concrete  example  of  the  shaft  and  hole 
diagramatically  shown  in  Figure  139.  This  illustra- 
tion shows  that  the  limits  as  set  for  the  dimension  of 
the  hole  are  given  in  terms  of  plus  (+)  and  minus  (— ) 
It  will  be  seen  that  the  shaft  sizes  are  also  given  in 
limits  but  that  the  limits  are  both  minus  dimensions. 


INTERNAL,  MXWmKH^     THREAD  GATOESmi 


From  the  figures  given  on  the  diagram,  the  greatest 
amount  of  variation  possible  is  as  follows: 

Maximum  hole  =  1.00025 
Minimum  shaft  =  0.098 

Clearance         =  0.00225 

Minimum  hole  =  0.99975 
Maxuaum  shaft  =  0.999 

Clearance         =  0.00075 

From  the  diagram  and  the  foregoing  figures  it  will 
be  seen  that  in  such  extreme  cases  the  allowance  or 
clearance  will  be  sufficient  to  obtain  a  running  fit  for 
the  shaft  in  the  hole.  It  is  true  that  in  the  greater 
extreme  the  clearance  is  a  little  more  tl|||^^  be, 
while  in  the  smaller  allowance  the  fit  is  a  little  closer 
than  it  should  be;  but  if  the  gauges  which  are  used  for 
the  work  are  properly  used,  there  will  be  no  doubt  that 
the  fits  obtained  are  commercially  good. 

The  principles  shown  in  this  diagram  can  be  applied 
to  other  kinds  of  gauging,  and  it  is  an  easy  matter  to 
determine  whether  the  proper  allowance,  tolerance,  and 
lunit  have  been  set  for  any  given  piece  of  work  by 
means  of  a  careful  inspection  of  the  results  in  mari- 
mum  and  minimum  sizes  obtained  by  following  the 
limit  given. 

Setting  Limits  for  fiiterchaiigeable  Work. — Gauging 
work  in  order  to  produce  interchangeable  parts  is  de- 
pendent upon  so  many  factors  that  it  is  out  of  the 
question  to  give  hard  and  fast  rules  here  that  will  be 
applicable  to  all  conditions.  Manufacturers  have 
established  no  system  of  limits  which  fit  every  con- 


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353 


INTBINAIj,  external,  and  thread  gauges  355 


ditionj  and  there  is  mor^  or  less  diversity  of  opinion. 
Tables  used  by  the  Newall  Engineering  Co.  are  given 
on  the  preceding  pages  which  may  be  helpful  to  a 
manufacturer  in  establishing  a  system  of  limits  for  his 
own  factory.  As  previously  stated,  the  class  of  work  to 
be  done  has  a  great  effect  on  the  setting  of  limits  for 
mterchangeable  manufacture,  but  a  basis  from  which 
to  work  can  readily  be  established  and  suitable  changes 
made  to  suit  requirements  which  later  may  be  found 
necessary. 

The  man  who  establishes  a  system  of  manufacturing 
limits  for  interchangeable  manufacture  must  always 
understand  the  requirements  of  the  work  to  be  done  and 
its  nature.  He  must  know  just  wfcere  the  finest  work- 
ing  parts  of  the  mechanism  are  situated  and  how 
closely  these  parts  must  be  fitted  in  order  to  give  the 
results  required.  The  conditions  of  manufacture  must 
always  be  considered,  and  the  vital  parts  of  the 
mechanism  must  have  special  attention.  As  pre- 
viously mentioned,  tolerances  for  all  work  should  be  as 
great  as  possible  consistent  with  the  quality  of  the 
work  to  be  produced. 

In  this  connection  it  is  well  to  mention  the  unfor- 
tunate practice  of  the  majority  of  manufacturers  in 
regard  to  shaft  lengths.  ,  It  is  seldom  that  they  pre- 
scribe limits  on  this  class  of  work,  and  therefore  the 
workman  in  making  a  shaft  is  unable  to  determine 
how  closely  the  shoulders  must  be  made  to  the  given 
sisses  on  the  drawing.  In  order  to  obviate  any  trouble 
in  this  regard  it  is  good  practice  to  establish  a  system 
of  some  sort  to  govern  such  work.  It  must  always  be 
remembered  that  small  tolerances  mean  careful  work 


m  TOOLS  AND  PATTERNS 


and  tliat  careful  work  is  always  expensive.  Therefore 
it  is  highly  advisable  to  specify  the  limits  on  shafts 
and  shoulders  in  order  to  obviate  difficulties  in  machin- 
ing. It  is  frequently  possible  to  give  shoulder  toler- 
ances on  shafts  of  1/64  or  1/32  of  an  inch,  and  when 
it  is  possible  to  give  such  tolerances  the  cost  of 
machining  will  be  much  more  reasonable. 

Many  manufacturers  set  tolerances  entirely  too 
dose  in  the  effort  to  obtain  a  fine  product.  Some 
even  go  to  the  expense  of  finishing  parts  which  do  not 
fit  others  in  order  to  improve  the  appearance  of  the 
finished  product.  Such  practice  as  this  is  expensive 
and  unneeessarjTy  except  in  cases  where  parts  must  be 
balanced  on  account  of  the  high  rate  of  speed  at 
which  they  are  to  run  or  else  to  prevent  vibration 
due  to  excessive  speed  and  lack  of  perfect  balance. 
All  these  points  must  be  considered  in  the  setting 
df  liinits,  and  therefore  it  is  very  obvious  that  the 
engineer  who  does  this  work  must  be  perfectly  fa- 
miliar with  the  product  in  its  actual  working  points. 

Maridng  Lunits  on  Drawings.— The  marking  of 
drawings  with  limits  is  commendable,  and  much  eon- 
fusion  can  be  avoided  by  using  fractional  dimensions 
for  aU  unimportant  sizes.  A  notation  can  be  made 
on  the  drawing  to  the  effec);  that  an  error  of  1/64  + 
or  —  is  permitted  on  fractional  dimensions  given  on 
the  drawing.  Decimal  dimensions  can  also  be  used 
to  indicate  tolerances  to  a  certain  degree,  although 
this  practice  in  general  is  not  recommended.  There 
may  be  a  notation  or  an  understanding  in  regard  to 
the  matter,  however,  such  that  if  decimal  dimensions 
are  given  to  four  places  of  decimals,  the  work  must 


INTBBNAL,  EXTERNAL  AND  THREAD  GAUGES  357 

be  kept  within  a  limit  of  plus  or  nunus  0.0005;  if 
three  places  of  decimals  are  given  on  a  drawing  then 
the  limit  is  to  be  kept  within  0.001  plus  or  minus; 
if  two  places  of  decimals  are  given  on  the  drawing 
then  it  may  be  understood  that  a  limit  of  0.005  plus 
or  minus  is  permissible.  The  better  way,  however,  is 
to  mark  the  drawings  positively  with  the  limit  when- 
ever possible,  so  that  there  is  no  chance  for  errors  on 
the  part  of  the  workman. 

Internal  Limit  Gauges.— If  it  is  necessary  to  ma- 
chine a  hole  within  certain  limits  of  accuracy,  a 
gauge  should  be  provided  which  is  so  constructed  as 
to  permit  the  workman  to  use  it  in  determining 
whether  he  has  produced  the  work  within  the  re- 
quired size  or  not.  If  the  hole  to  be  measured  is  a 
cylindrical  one  of  small  size,  say  2  or  2%  inches,  then 
the  type  of  gauge  which  is  used  is  termed  a  plug 
gauge.  And  if  the  hole  to  be  gauged  is  tapered,  the 
type  of  gauge  used  is  termed  a  taper  plug  gauge.  If 
the  hole  is  threaded,  the  gauge  used  is  called  a  male 
thread  gauge.  These  three  gauges  are  of  different 
types  and  are  made  differently  to  suit  the  various 
kinds  of  work  for  which  they  are  to  be  used. 

A  limit  gauge  is  a  gauge  so  constrncted  as  to  de- 
termine more  or  less  automatically  whether  work  has 
been  made  within  the  specified  limits  or  not.  There 
are  several  types  of  gauges  for  this  purpose,  which 
differ  from  each  other  only  in  certain  details  of  con- 
struction; the  principles  on  which  they  are  based  are 
the  same.  The  type  used  for  gauging  a  cylindrical 
hole  has  one  end  made  of  such  mm  that  it  will  just 
enter  the  hok  providing  the  hole  has  been  made  large 


358 


TOOLS  AND  PATTERNS 


60 


N  OT  60 


00 


NCT  OO 


00 


NOT  60 


no.  140.    SEVERAL  VARIETIES  OF  PLUG  GAUGES 


enough;  the  other  end  is  very  slightly  larger  than  the 
hole  should  be,  the  difference  in  size  being  the  ex- 
treme limits  or  tolerance  permitted  in  the  work. 
Therefore  a  gauge  of  this  kind  is  frequently  spoken 
of  as  a  ''go  and  not  go"  gauge,  meaning  that  one 
end  should  go  into  the  work  and  the  other  end  should 
not  go.  Sometimes  the  go  and  not  go  portions  are 
on  the  same  end  of  the  gauge. 

Beferring  to  Figure  140,  the  two  types  of  gauges 
commonly  used  will  be  noted  at  A  and  B.  The 
upper  figure,  A,  shows  the  double-end  plug  gauge, 
and  the  lower  figure,  B,  has  both  of  the  limiting 
portions  on  one  end.  The  lower  type,  B,  is  to  be  pre 
ferred  for  work  in  which  the  hole  extends  cona- 
pletely  through  the  piece,  as  the  workman  in  this 


iNTBRNAIi,  BXf  BBNAL  AND  THEEAD  GAUGES  359 

case  is  not  obliged  to  turn  the  gauge  end  for  end  in 
using  it.  These  gauges  are  often  made  with  a  slight 
taper  on  the  end,  in  order  to  facilitate  their  use. 

Another  type  of  plug  gauge  for  cylindrical  work  is 
shown  at  C  in  the  same  figure.  This  gauge  does  not 
differ  from  the  one  indicated  at  A  in  any  respect  ex- 
cept that  the  go  and  not  go  portions  are  made  in  the 
form  of  bushings  which  can  be  removed  and  replaced 
with  others  in  the  event  of  their  becoming  worn. 
Although  gauges  of  this  kind  cost  a  little  more  to 
produce,  they  have  many  advantages,  which  are 
plainly  apparent,  in  the  line  of  upkeep. 

Intamal  Taper  Gauges.— The  gauging  of  a  tapered 
hole  is  an  entirely  different  proposition  from  the 
gauging  of  a  cylindrical  one,  for  two  gaugings  are  re- 
quired, namely,  the  taper  itself  and  the  diameter  at 
the  large  end  of  the  hole.  It  is  obvious  that  a 
tapered  hole  is  made  to  fit  a  tapered  shaft  or  some- 
thing of  similar  nature.  In  a  gear  which  is  made 
with  a  taper  hole,  for  instance,  the  gear  must  be 
made  to  mesh  correctly  with  its  mate,  and  therefore 
its  longitudinal  position  on  the  tapered  shaft  is  im- 
portant. This  means  that  the  tapered  portion  must 
be  of  such  a  diameter  at  the  large  end  that  it  will 
slip  upon  the  tapered  shaft  to  a  definite  distance 
and  fit  snugly  on  the  shaft  at  the  same  time  that  it 
attains  its  correct  position  longitudinally.  It  is  plain, 
then,  that  a  gauge  for  such  a  piece  of  tapered  work 
must  be  so  made  that  it  will  determine  the  taper  as 
well  as  the  distance  that  the  actual  fit  will  take 
place  on  the  shaft. 

As  it  is  rather  difficult  to  measure  a  tapered  hole 


360 


TOOLS  AND  PATTERNS 


at  the  large  end,  or  in  fact  in  any  other  portion  of 
the  hole,  without  special  instruments.  The  method 
used  in  gauging  the  diameter  is  by  the  distance  that 
a  marked  section  of  the  gauge  enters  the  large  end 
of  the  work.  By  reference  to  Figure  141,  the  type 
of  gauge  used  for  a  tapered  hole  will  be  clearly 
noted.   This  gauge  is  a  limit  taper  gauge,  and  the 


WG.  141.    TAPER  UMIT  GAUGE  FOR  INTERNAL.  TAPERED  HOLE 

limiting  portions  are  determined  by  the  flatted  part, 
B,  on  one  side  of  the  gauge  and  the  cylindrical  por- 
tion, C,  which  extends  beyond  it.  Now  when  this 
gauge  is  used  in  a  tapered  hole,  the  operator  places 
it  in  position  and  notes  whether  the  flatted  portion  is 
below  the  surface  of  the  hole  or  not.  If  he  finds 
that  it  is  below  the  surface  and  that  the  opposite 
side  of  the  gauge,  C,  remains  slightly  outside  of  the 
work,  then  he  is  certain  that  the  work  has  been  made 
within  the  required  limit  longitudinally. 

In  addition  to  the  longitudinal  dimension,  how- 
ever,  it  is  necessary  to  determine  whether  the  taper 


INTERNAL,  EXTERNAL  AND  THREAD  GAUGES  3(ii 


MO.  142.    FEMAU:  MASTER  GAUGE  FOE  TESTING  MALE 

TAPEE  GAUGES 

is  correct  or  not.  As  a  general  thing  the  taper  in  a 
hole  is  determined  by  means  of  a  special  tapered 
reamer  and,  therefore,  there  is  little  chance  for  varia- 
tion at  this  point.  However,  in  order  to  determine 
the  taper  with  certainty,  the  inspector  may  use  a 
little  Prussian  blue  on  the  gauge  and  by  revolving 
it  slightly  in  the  hole,  he  may  see  whether  it  is  in 
contact  along  its  entire  length  or  not. 

In  connection  with  the  use  of  taper  gauges  and,  in 
fact,  other  types  of  gauges,  mention  should  be  made 
of  the  necessity  for  reference  gauges.  Gauges  of 
this  kind  are  made  with  great  care  and  should  be 
kept  in  a  safe  place  so  that  they  will  not  be  subject 
to  injury  or  marked  variations  in  temperature.  It 
is  apparent  that  a  reference  gauge  for  a  male  taper 
gauge,  such  as  that  just  described,  would  be  such 
that  when  placed  in  conjunction  with  the  reference 
gauge  any  variation  might  be  readily  detected.  A 


362 


TOOLS  Am  PATTBI^S 


male  gauge  is  usually  tested  by  placing  it  in  a 
female  gauge,  and  conversely  a  female  gauge  is 
tested  on  a  male  gauge. 

When  a  number  of  tapers  of  different  diameters 
but  of  the  same  angle  are  to  be  tested,  a  reference 
gauge  like  that  shown  in  Figure  142  can  be  readily 
made.  This  gauge  is  marked  with  the  piece  numbers 
and  the  limits  in  such  such  a  way  that  the  accuracy 
of  the  gauge  to  be  tested  can  be  quickly  determined. 
This  gauge  is  made  with  three  adjustable  blades  of 
steel  to  facilitate  manufacture.  After  the  gauge  has 
been  set  properly  by  means  of  suitable  measuring  in- 
struments, the  screw  holes  can  be  filled  with  wax  or 
composition  so  that  they  cannot  be  tampered  with. 

Male  Thread  Gauges. — ^When  an  internal  thread  is 
to  be  ganged  the  type  of  gauge  used  is  generally 
called  a  male  thread  gauge.  The  gauging  of  a  thread 
requires  special  precautions  as  there  are  so  many 
points  to  be  determined:  First,  theVe  is  the  diameter 
of  the  thread  at  the  pitch  line;  second,  the  angle  of 
the  thread;  third,  the  diameter  of  the  hole  at  the 
bottom  of  the  thread;  fourth,  the  lead  of  the  thread.* 
The  ordinary  commercial  gauge  only  gives  an  ap- 
proximation of  these  four  points,  otherwise  several 
gauges  would  be  needed  to  determine  whether  a 
thread  was  correctly  made  or  not. 

The  simplest  form  of  thread  gauge  is  a  piece  of 

♦The  lead  of  a  thread  is  the  distance  from  the  center  of  one 
thread  to  the  center  of  the  next«  measured  longitudinally.  That  Is. 
In  a  16  pitch  thread,  the  lead  is  i  inch,  because  there  are  16  threads 
to  the  inch.  On  multiple  threads,  i.  c,  double  or  quadruple  threads. 
lead  denotes  the  longitudinal  distance  from  one  thread  to  the  same 
thread  after  it  has  passed  once  around  the  piece.  Thus  the  lead  -of  ft 
16  pitdi  thread  qiiadnqile,  would  be  4x  ^  =  H  incb.  • 


UNTKRNAL,  EXTERNAL  AND  THREAD  GAUGES  3a 


steel  threaded  on  both  ends,  one  end  of  which  is 
made  so  as  to  enter  the  threaded  hole  and  the  other 
end  slightly  larger  so  that  it  will  not  enter  the 
threaded  hole.  This  type  of  gauge  is  clearly  shown 
in  Figure  143.  Commercially,  a  gauge  of  this  type 
gives  results  sufl&ciently  close  to  the  limit. 

The  majority  of  threaded  holes  are  made  by  taps, 
and  if  the  thread  gauge  does  not  enter  the  work 
freely,  it  is  generally  found  that  something  is  the 


FIG.  143.    STANDARD  TYPE  OF  MAO:  THBEAD  QAVm 


matter  with  the  tap  that  has  been  used.  The  taps 
should  then  be  examined  to  find  where  the  error  lieis 
and  be  discarded  if  found  faulty.  In  most  cases  it 
will  be  found  that  a  variation  in  the  lead  is  the  cause 
of  the  trouble.  The  tap  may  have  been  made  up 
properly  and  have  changed  considerably  during  the 
hardening  process,  so  as  to  give  a  lead  slightly  dif- 
ferent from  what  it  should  be.  It  is  an  easy  matter 
for  a  workman  to  tap  a  hole  to  the  proper  size,  but 
'f  the  lead  of  his  tap  is  incorrect,  great  difficulty  may 
be  found  in  assembling  the  parts  after  they  have 
been  machined.  A  variation  in  the  lead  of  the  thread 


11 


364 


TOOLS  AND  PATTERNS 


INTEBNAL,  EXTERNAL  AND  THREAD  GAUGES  365 


means  that  only  a  few  threads  will  be  doing  all  the 
work  while  the  other  ones  are  free. 

Several  inBtraments  are  made  for  measuring  the 
lead  of  a  serew,  based  on  the  pitch  line  m^ure- 
ment.  Usually  these  instruments  are  provided  with 
ball  points  to  reach  down  into  the  thread  and 
measure  directly  on  the  pitch  line.  The  type  of 
thread  gauge  shown  in  the  illustration  is  practically 
the  only  one  which  is  commercially  used  today.  The 
amount  of  tolerance  permitted  should  never  be  more 
than  70  to  80  per  cent  of  a  full  thread. 

Some  gauges  are  made  in  such  a  way  that  a  por- 
tion of  the  gauge  will  act  as  a  plug  to  measure  the 
root  of  th-e  thread  or,  really,  the  diameter  of  the 
hole.  In  this  case  the  thread  itself  is  measured  sepa- 
rately. The  majority  of  commercial  screws  are  made 
with  two  much  clearance;  this  results  in  a  loss  of 
strength  and  is  productive  of  considerable  difficulty 
when  used  on  machinery  otherwise  all  right.  The 
result  of  poor  workmanship  on  threaded  work  is  that 
the  threads,  not  having  a  full  bearing,  strip  easily 
and  are  generally  useless.  The  limit  on  threaded 
work  should  be  sufficient  to  avoid  such  conditions. 

Ixtanal  Oaiigea.— External  gauges  are  made  for 
cylindrical,  taper,  or  threaded  work.  There  are  sev- 
eral kinds:  snap  gauges,  ring  gauges,  receiver  gauges, 
and  female  thread  gauges.  The  snap  gauge  is  the 
most  common  and  is  used  for  gauging  cylindrical 
work.  The  ring  gauge  is  generally  used  for  reference, 
although  occasionally  it  is  used  for  actual  gauging 
processes.  Receiver  gauges  are  made  for  determining 
several  diameters  at  the  same  time  and*  also  for  taper 


MG.  144.    STANDARD  TYPE  OF  SNAP  GAUGE  YTTTH 
ADJUSTABLE  POINTS 

work.  The  female  thread  gauge  is  used  for  gauging 
male  threaded  work,  such  as  screws  and  the  like. 

In  gauging  cylindrical  work  which  is  to  be  held 
within  definite  limits  of  accuracy,  the  snap  gauge 
shown  in  Figure  144  is  commonly  used.  This  gauge 
is  provided  with  surfaces  or  pins  which  limit  the 
amount  of  variation,  as  shown  at  A  and  B  in  the 
illustration.  The  '^go"  portion  of  the  gauge  is  rep- 
resented at  A;  the  "not  go"  at  B,  This  gauge  is 
used  directly  on  the  work  and  is  extremely  simple. 
As  an  example,  let  us  suppose  that  a  piece  of  cylin- 
drical work  is  to  be  held  within  the  dimension  0.998 
and  0.996.  Then  A  would  be  made  0.998  and  B, 
0.996;  hence  if  the  work  were  to  be  made  so  that  it 
will  enter  A  and  not  go  between  the  points  B,  it  is 


m  TOOLS  AND  PATTERNS 


flG.  145.     SNAP  GAUGE  FOR     FIG.  146.  TEMPLET  GAUGE  FOR  A 
IIOBE  THAN  ONE  DIMENSION  SPECIAL  STUD 

sure  to  be  right.  When  this  gauge  becomes  worn, 
the  points  A  and  B  can  be  adjusted  by  size  blocks  or 
regronnd  to  size.  In  order  to  avoid  either  acci- 
dental or  intentional  changes,  it  is  well  to  pour 
melted  wax  into  the  holes  at  the  adjustable  points,  or 
else  to  put  a  drop  or  two  of  solder  at  these  points  so 
that  no  change  can  possibly  be  made  without  per- 
mission from  the  inspection  department. 

Snap  Ganges  for  Widths.— Gauges  of  the  snap 
variety  are  also  used  for  determining*  widths  across 
lugs  and  between  them,  for  shoulder  distances  on 
shafts,  for  distances  between  bearings,  and  for  other 
work  of  like  character.  Sheet  metal  gauges  are  fre- 
quenUy  made  for  this  purpose,  and  several  gauging 

points  can  bemiill  I  HIWl  ingle  gauge.  For  examp^ 

having  a  casting,  such  as  shown  above  in  Figure  1^^ 
in  which  the  dimensions  A  and  B  are  to  be  gauged, 
a  snap  gauge  similar  to  that  shown  in  the  lower  por 


INTERNAL,  EXTERNAL  AND  THREAD  GAUGES  367 


tion  of  the  figure  can  be  employed.  This  type  of 
gauge  is  made  up  of  sheet  steel,  usually  Vs  to  3/16 
inch  in  thickness,  and  hardened  after  it  has  been 
made  very  close  to  size.  After  the  hardening,  the 
gauging  points  or  surfaces  are  carefully  ground  to 
correct  dimensions.  Gauges  of  this  kind  can  be  used 
in  confined  situations,  and  as  they  can  be  cheaply 
made  their  use  is  almost  infinite. 

Templet  Gauges. — Frequently  it  is  necessary  to 
determine  the  form  of  a  piece  of  work  after  it  has 
been  machined,  especially  when  the  shape  of  the 
piece  is  more  or  less  irregular.  Take  as  an  example 
the  work  sho\\Ti  in  Figure  146,  in  which  the  general 
form  and  correct  spacing  of  A,  B,  and  C  are  essential. 
In  a  case  of  this  kind  a  templet  gauge,  similar  to 
that  shown  at  D,  can  be  made  to  the  form  desired 
and  the  workman  can  use  it  when  making  up  the 
piece,  applying  it  to  the  work  from  time  to  time  to 
obtain  correct  spacing  and  foriii. 

The  templet  gauge  as  ordinarily  used  is  not,  how- 
ever, an  accurate  method  of  gauging  for  it  does  not 
**tell  the  story,"  but  only  determines  whether  the 
shape  of  the  work  is  correct  or  not.  It  does  not  show 
just  where  the  points  of  inaccuracy  are,  but  it  does 
show  that  the  piece  is  not  correct  if  it  does  not  fit 
the  gauge.  When  it  is  necessary  to  gauge  the  con- 
tour of  a  piece  of  work  within  close  limits  of  accu- 
racy, another  type  of  measuring  instrument,  termed 
an  indicating  gauge,  can  be  used.  This  type  will  be 
described  in  the  next  chapter. 

Perhaps  one  of  the  most  useful  appBcations  of  the 
templet  gauge  is  in  the  manufacture  of  bolts,  cap 


368 


TOOLS  AND  PATTERNS 


FIG.  147.    TEMPUBT  GAUGE  FOB  A  SCREW 

screws,  studs,  and  the  like,  for  determining  the 
length  of  the  work  and  the  length  of  the  thread.  As 
an  example,  let  us  take  the  screw  shown  in  Figure 
147  in  which  the  length,  A,  is  3  inches  and  the  length, 
B,  of  the  thread,  2  inches.  A  gauge  can  be  made  for 
this  work  similar  to  that  shown  in  the  lower  part  of 
this  illustration.  Its  application  is  obvious:  both  the 
length  of  the  work  and  the  thread  can  be  noted  in  an 
instant  when  the  gauge  is  applied.  There  are  many 
other  uses  to  which  the  templet  gauge  can  b®* 
adapted,  and  the  forms  used  are  naturally  dependent 
upon  the  work  to  which  they  are  to  be  applied. 

Ring  Gauges  for  Cylindrical  Work.— Bing  gauges, 
such  as  that  shown  in  Figure  148  at  K,  are  used  m 
a  large  degree  for  reference,  but  they  are  also  occa- 
sionally called  for  in  connection  with  manufacturing 


INTERNAL,  EXTERNAL  AND  THREAD  GAUGES  369 


on  certain  classes  af  work.  The  ordinary  snap  gauge 
as  used  on  cylindrical  work  simply  gives  the  diameter 
of  the  work  at  certain  places  where  it  is  applied,  but 
it  does  not  show  the  variations  along  the  shaft,  nor 
does  it  determine  whether  the  work  is  uniform  in  size 
at  all  points. 

Let  us  take  the  piece  of  work  shown  in  Figure  148 
as  an  example:  Here  we  see  a  shaft  on  which  another 
member  is  to  have  a  sliding  fit  from  A  to  B.  In 
gauging  this  shaft,  the  snap  gauge  would  be  used  at 
two  or  three  points,  as  at  C,  D,  and  E,  and  it  will 
be  assumed  that  the  remainder  of  the  shaft  is  correct, 
providing  these  points  pass  the  inspection.  By  re- 
ferring to  the  exaggerated  view,  much  enlarged,  of 
the  same  shaft,  it  can  be  seen  that  if  the  work  is 
found  to  be  imperfect,  as  shown  at  F,  G,  and  H,  the 


■ 

u  ^ 

 ^ 

1 

*          A  A 

t — 1 

F. 

d   c  r 

Q 


D' 


FIG.  148.    CTMNDMCAL  RING  GAUGE,  SHOWING  APPUCATION 


S70 


TOOLS  AND  PATTERNS 


snap  gauge  will  not  reveal  the  defect  Bat  if  the  ring 
gauge,  K,  were  to  be  passed  over  the  work  from  A  to  B, 
the  trouble  would  be  located  immediately.  For  work 
of  this  kind,  therefore^  the  snap  gauge  can  be  used 
as  a  work  gauge  and  the  ring  gauge  for  the  final  in- 
spection. The  workman  can  then  gauge  the  work  for 
diameter,  and  the  inspector's  test  with  the  ring  gauge 
will  show  any  variations  along  the  length. 

Reoeivitor  Ganges. — On  certain  classes  of  work,  such 
as  the  components  of  rifles,  sewing  machines,  type- 
writers, and  adding  machines,  it  may  be  found  neces- 
sary to  gauge  every  part  of  the  piece  as  a  final  check 
against  errors  in  machining.  In  this  work  a  receiver 
gauge  can  be  employed  to  advantage.  This  instrument 
is  so  made  that  the  work  can  be  placed  in  the  gauge 
itself,  and  if  'the  piece  of  work  has  been  correctly  made 
within  the  required  limits  of  accuracy,  it  will  conf  oni 


m.  140.  EExmvm  oaugs  fob  tafeb  hns 


INTIBNAL,  EXTEENAIi  A^fg/gmM)  aAUGES  371 


closely  to  the  contour  of  the  receiver.  Gauges  of  this 
kind  can  be  made  as  limit  gauges  if  desired,  either  by 
making  them  up  with  a  series  of  sliding  points  to  in- 
dicate the  limits  of  variations  permissible,  or  by 
making  two  gauges  in  one  of  which  the  work  must 
go  and  in  the  other  not  go.  Sometimes  it  is  neces- 
sary to  gauge  a  contour  very  carefully,  and  in  cases 
of  this  kind  an  indicating  gauge  can  be  employed,,  as 
described  in  the  next  chapter. 


MG.  150.     RECEIVER  GAUGE  FOR  A  POPPET  VALVE 

A  common  form  of  receiver  gauge  is  that  shown  in 
Figure  149,  which  is  made  for  taper  pins.  Keference 
to  the  illustration  will  show  that  it  consists  of  a  base 
plate  and  two  blades,  one  of  which  may  or  may  not  be 
adjustable.  In  using  this  type  of  gauge  the  pin  is 
simply  laid  between  the  two  blades  in  order  to  note 
whether  the  taper  corresponds  to  that  of  the  gauge 
or  not.  An  additional  refinement  can  be  incorporated 
in  this  gauge  by  placing  a  mark  on  one  of  the  blades 
to  gauge  the  diameter  of  the  taper  pin  by  determin. 
ing  its  length. 


372 


TOOLS  AND  PATTBKNS 


Another  application  of  the  receiver  gange  is  shown 
in  Figure  150.  This  gauge  is  made  for  a  poppet 
valve,  in  order  to  test  the  concentricity  of  the  stem, 
Ay  and  the  valve  seat,  B.  In  addition  to  these  points 
the  angle  of  the  seat  can  also  he  ganged.  It  will  be 
noted  that  a  part  of  the  collar,  C,  is  cut  away  to 
permit  inspection  along  the  seat  of  the  valve.  Many 
applications  of  this  type  of  gange  can  he  made  when 
the  nature  of  the  work  warrants  it. 

Taper  Ring  Gauges. — In  gauging  a  taper  shaft  or 
work  of  similar  character  several  varieties  of  gauges 
may  be  used.  These  gauges  are  usually  made  from  a 
cylindrical  piece  of  steel  having  a  tapered  hole,  such 
as  that  shown  in  Figure  151  at  A.  The  limits  are 
taken  care  of  by  cutting  away  half  of  the  gauge  at 
the  large  end,  as  noted  at  B.  The  correct  size  is  de- 
termined by  the  junction  of  the  tapered  portion  with 
the  cylindrical  part  and  the  position  of  the  gauge 


no.  151.    FEMALE  TAPER  UIOT  GAUGE 


INTKBSAL,  EXTBENAIi  AND  THREAD  GAUGES  373 

longitudinally  on  the  work.  The  gauge  should  not 
push  onto  the  work  far  enough  so  that  the  flat  part 
comes  beyond  the  junction  of  the  tapered  and  the 
cylindrical  part.  The  taper  itself  is  found  to  be  cor- 
rect or  not  by  placing  the  gauge  in  position  on  the 
work  which  has  been  coated  with  a  thin  film  of  Prus- 
sian blue  and  giving  it  a  slight  turn  to  determine 
whether  the  taper  is  touching  at  all  points. 


FIG.  152.    MALE  MASTER  GAUGE  FOR  TESTING  FEMALE 

TAPER  GAUGES 


Master  Taper  Gauge  for  Female  Gauges. — ^As  a 

reference ,  gauge  to  which  a  female  gauge  may  be 
applied  in  order  to  determine  whether  it  is  correct  or 
not,  a  form  such  as  that  shown  in  Figure  152  can  be 
advantageously  used  when  all  of  the  tapers  to  be 
gauged  have  the  same  angle.  This  gauge  was  de- 
signed to  go  with  the  female  gauge  shown  in  Figure 
142.  But  in  this  case  the  gauge  is  intended  for  test- 
ing female  taper  gauges  while  the  other  is  intended 
for  testing  male  taper  gauges.   It  will  be  seen  that 


374 


TOOLS  AND  PATTEBNS 


HG.  153.  FEMAo:  thread  oauge 


there  are  three  blades,  A,  which  are  set  into  a  column 
of  steel  supported  by  a  base,  B.  Along  the  blades, 
the  limits  for  various  sizes  of  tapers  are  marked,  as 
indicated  at  C,  D,  E,  P,  etc.  In  use,  then,  a  master 
gauge  of  this  kind  is  set  up  on  its  base,  the  ring 
gauge  is  dropped  over  it,  and  an  inspection  will  de- 
termine whether  the  ring  gauge  is  made  correctly 
both  as  to  limit  and  proper  taper.  Gauges  of  this 
kind  which  are  intended  for  reference  only  should  be 
preserved  very  carefully  and  never  used  for  anything 
except  reference.  ^ 

Female  Thread  Gauges.— When  a  piece  of  threaded 
work,  such  as  a  shaft  or  stud,  is  to  be  gauged  on  its 
threaded  portion,  the  testing  is  usually  done  by  screw- 
ing the  work  into  a  female  thread  gauge,  such 
as  that  shown  in  Figure  153.  This  gauge  is  made 
from  a  piece  of  steel  of  rectangular  form  and  is 
drawn  toffeih^r  or  separated,  as  the  case  may  require, 
hj  means  of  the  set  screws  indicated  at  A  and  B. 


INTBBNAL,  BXTEBNAL  AND  THREAD  GAUGES  375 


Adiustment  is  simply  for  the  purpose  of  fimshmg  the 
14e  to  the  correct  size  with  as  little  difficulty  m 
possible.  It  also  provides  a  slight  adjustment  after 
the  gauge  has  become  worn. 

Gauges  of  this  kind  are  seldom  made  with  limits; 
but  for  very  particular  work  two  gauges  can  be  used, 
one  of  the  -go''  variety  and  the  other  of  the  not 
ffo  "  For  ordinary  commercial  work  which  does  noi 
require  very  close  limits  of  accuracy  a  gauge  of  this 
kmd  will  be  found  sufficient. 

For  determining  whether  the  lead  of  the  thread  is 
correct,  a  separate  instrument  must  be  used,  as  de- 
scribed in  the  next  chapter.  In  general,  threads  ot 
this  kind  are  not  gauged  for  the  lead  unless  they 
are  particularly  important,  in  which  case  the  in- 
dicating type  of  gauge  is  used  to  determme  the  cor- 

''^Therf  are  other  types  of  external  and  internal 
gauges  which  are  used  for  special  purposes,  but  the 
maiority  of  them  are  modifications  of  those  whicn 
have  been  shown  or  else  they  are  of  the  indicating 
type  of  gauge  for  determining  variations  m  mside 
or  outside  contours.  The  description  of  such  of  these 
gauges  as  are  not  mentioned  in  this  chapter  will  be 
taken  up  in  the  following  chapter. ' 


CHAPTER  XXIV 


PBOFILE  AND  INDICATING  GAUGES 

Gauges  for  High  Accuracy. — ^The  present  tendency 
in  gauging  methods  is  to  do  away  as  far  as  possible 
with  all  gauges  which  do  not  show  the  amount  of 
variation  in  the  work.  Many  of  the  gnHH  described 
in  the  previous  chapter  are  made  to  indicate  whether 
a  piece  of  work  has  been  finished  within  the  required 
limits  or  not.  The  workman,  in  using  ordinary  limit 
gauges,  has  no  means  of  knowing  (except  the  sense 
of  feeling)  how  nearly  he  is  approaching  the  limits 
which  are  permissible.  His  first  real  knowledge  that 
his  tools  have  **gone  the  limit"  is  when  his  gauge 
tells  him  so.  Hence  it  will  be  seen  that  for  work 
requiring  a  high  degree  of  accuracy,  the  ordinary 
types  of  limit  gauges  do  not  quite  answer  the  pur- 
pose. For  such  conditions,  then,  some  other  type  of 
instrument  by  means  of  which  the  actual  variations 
in  the  work  can  be  accurately  determined,  is  essen- 
tial. 

Now  let  us  see  what  principles  can  be  used  in 
gauging  work,  keeping  it  within  the  prescribed  limits 
and  at  the  same  time  indicating  the  variations  which 
are  taking  place  from  time  to  time  because  of  the 
wear  and  changes  in  size  of  cutting  tools.  It  is  evi- 
dent that  indicating  instrum^ts  which  will  show 


FlOFILl  AND  INDICATING  GAUGES  377 


variations  in  the  work  make  it  possible  for  the  work- 
man to  change  his  tools  as  may  become  necessary 
and  thus  keep  the  work  much  closer  to  size  than  if 
the  ordinary  limit  illpes  were  used. 

For  instruments  ofliis  kind  variations  in  the  work 
can  be  shown  by  a  pointer  of  some  sort  working  over 
a  graduated  scale;  by  the  sense  of  touch  in  the  work- 
man's fingers  as  they  are  passed  over  one  or  more 
movable  points;  or  by  the  sense  of  hearing,  as  in  the 
case  of  a  gauge  showing  limits  by  an  electric  contact 
which  rings  a  bell  or  operates  a  buzzer.  Of  these 
three  types,  the  dial-indicating,  or  multiplying-leyer 
type,  is  most  common.  This  gauge  has  a  sensitive 
movable  pointer  which  works  on  a  graduated  scale  or 
dial,  and  can  be  adapted  to  an  infinite  number  of 
uses  in  gauging.  The  **feeler"  or  **flu&h  pin"  gauge 
is  also  used  to  a  considerable  extent  on  work  of 
irregular  form,  or  for  depth  gauging;  it  is  sometimes 
found  convenient  to  use  it  also  in  the  case  of  deter- 
mining a  correct  shoulder  distance.  Micrometer 
gauges  are  also  used  to  some  extent  on  work  requir- 
ing the  highest  degree  of  accuracy.  And  finally, 
there  is  a  type  of  gauge  which  employs  a  delicate  and 
sensitive  arm  so  arranged  that  it  multiplies  the 
actual  variation  in  a  piece  of  work;  if  the  variation 
is  too  great,  it  rings  a  bell  by  an  electrical  contact, 
or  shows  a  red  or  green  light  if  this  scheme  is  pre- 
ferred. 

Standacrd  Instimments  of  Predston.— Any  mention 
of  gauging  systems  which  does  not  include  some  of 
the  standard  measuring  instruments  would  be  in- 
complete, but  as  we    e  for  the  most  part  concerned 


378 


TOOLS  AND  PATTEBNS 


SECTIONAL  VIE>N  OF 
MiCROMfJER  CAUPCR 


MICROMETER  HEM> 


HQ.  154.    MICROMETER  GAUGES  SHOWINQ  CONSTEOCTION 

FEATURES 

with  special  gauges,  we  will  not  devote  a  great 
amount  of  space  to  instruments  which  are  adapted  to 
the  most  minute  variations,  such  as  micrometer  and 
vernier  calipers  and  other  instruments  of  precision. 
But  as  the  principles  on  which  these  instruments 
are  hased  are  also  applied  to  gauging  certain  kinds 
of  work,  let  us  look  into  the  fundamental  pomts  on 
which  they  depend  for  their  accuracy.  . 

The  micrometer  caliper,  shown  in  Figure  154,  is 
familiar  to  all,  and  a  brief  description  is  all  that  will 
be  necessary.  The  upper  portion  shows  at  A  a  gen- 
eral view  of  the  instrument;  a  sectional  drawing  jusi 
below,  gives  an  excellent  idea  of  the  constructio^ 
The  frame,  B,  m  a  drop  forging  which  is  supplied! 


PBOFILE  AND  INDICATINa  GAUGES  379 

with  a  hardened  inserted  anvil,  C.  The  frame  is 
bored  out  and  has  an  adjusting  nut,  K,  iiisid|||||d  a 
short  nut,  L,  to  compensate  for  the  wear  on  thte 
threads.  The  screw,  D,  is  threaded  at  E,  and  is  fast- 
ened to  the  thimble,  G,  so  that  it  can  be  rotated  by 
the  fingers  of  the  operator.  Bach  revolution  of  the 
screw  moves  it  longitudinally  0.025  inches.  The  upper 
view  shows  the  graduation  on  the  thimble;  and  as 
there  are  25  of  these,  starting  with  0  and  running  to 
25,  each  division  represents  0.001  inch.  It  will  be 
seen  that  by  placing  the  work  between  the  points  C 
and  D  and  adjusting  the  screw  by  means  of  the 
thimble,  an  accurate  reading  can  be  easily  obtained. 
This  type  of  instrument  is  used  all  over  the  world  for 
accurate  measuring.  The'  micrometer  head  shown  in 
the  lower  portion  of  the  same  figure  is  sold  as  a 
separate  instrument  and  can  be  applied  to  many 
forms  of  gauging  by  mounting  it  on  a  suitable  fixture 
to  conform  to  the  work  which  is  being  gauged. 

Dial  Indicator. — ^Another  form  of  gauge,  useful  for 
inspecting  a  number  of  parts  of  the  same  kind,  is 
shown  in  Figure  155.  This  instrument  may  be 
adapted  to  a  variety  of  work  by  mounting  it  on  a 
suitable  holder  to  fit  the  conditions.  It  should  not 
be  considered  as  a  gauge,  however,  but  more  as  an 
indicator  to  show  variations  in  size  after  setting  it  to 
a  size  block  or  plug.  This  instrument  consists  of  the 
base,  A,  on  which  is  erected  a  vertical  shaft,  B, 
absolutely  perpendicular  to  the  base.  A  sliding  lever 
acts  on  this  shaft  m  a  holder  for  the  dial  indicator, 
C.  The  sleeve  can  be  vertically  adjusted  and  clamped 
at  any  desired  height  by  means  of  a  thumb  screw 


TOOLS  AND  PATTERNS 


TO.  155.    Aim  MAh  TOT  rnVGE  ABRANOED  FOB  INSPECTION 


(mi  shown)  at  the  rear  of  the  instrument.  The  gauge 
point,  D,  is  connected  with  the  dial  by  means  of  a 
multiplying  device  inside  of  the  instrument  case,  and 
the  dial  is  graduated  to  read  in  thousandths  of  an  inch, 
or  finer  if  desired.  In  operation,  a  plug  of  the  desired 
size,  similar  to  that  shown  at  S,  is  used  for  setting 
the  gauge  and  indicator  so  that  the  pointer  will  read 
0  if  the  work  is  correct.  A  piece  of  work,  such  as 
shown  at  E,  is  then  passed  under  the  gauge  point,  D, 
and  the  reading  is  noted.  Variations  can  he  quickly 
determined  in  this  way,  and  a  number  of  pieces  tested 
one  after  the  other.  Indicators  of  this  type  are  also 
frequently  mounted  on  special  gauging  fixtures  for 
special  work. 

Prestwich  Fluid  Gauge— There  has  been  a  demani 
for  many  years  for  an  accurate  indicating  gauge 
reading  to  one  ten-thousandth  part  of  an  inch  or 
finer,  and  a  number  of  instruments  are  now  on  the 
market  which  will  give  readings  as  close  as  this,  bit 


TO.  156.    FllSfWI09  WLVm  OAUCH 


382 


TOOLS  AMD  FAfTSENS 


they  are  quite  delicate  m  construction  and  require 
careful  handling  as  well  as  care  in  reading. 

The  recently  developed  gauge  shown  in  Figure  156, 
however,  answers  the  demandB  of  modern  engineering 
work  most  admirably,  md  the  reading  of  the  instn- 
ment  is  so  plain  that  a  variation  of  one  ten-thou- 
sandths part  of  an  inch  is  discernible  across  an  ordi- 
nary room.  Furthermore  the  work  can  be  gauged  to 
specified  limits,  with  the  gauge  set  to  meet  the  re- 
quirements of  the  work. 

For  ball  bearings,  thread  gauges,  or  any  other  work 
which  needs  to  be  calibrated  in  large  quantities  and 
within  very  close  limits  of  accuracy,  an  instrument  of 
this  kind  is  indispensable.  The  principles  involved  in 
the  construction  are  as  follows:  A  fluid-containing 
chamber,  A,  is  provided  with  a  flexible  diaphragm, 
B,  and  a  glass  tube,  C,  finely  bored  and  connected 
with  the  chamber,  A.  The  diaphragm,  B,  is  furnished 
with  a  hardened  steel  pin  or  anvil,  D,  and  the  base  of 
the  instrument  also  has  a  fixed  anvil,  E,  between 
which  and  the  anvil,  D,  the  work  is  passed  when 
calibrating.  The  chamber,  A,  contains  a  colored 
liquid  which  rises  and  falls  in  the  glass  tube,  C, 
according  to  the  pressure  applied  to  the  anvil,  D,  and 
transmitted  to  the  diaphragm.  The  lil||i|||!ira  of  the 
diaphragm  in  comparison  with  the  fine  hole  for  the 
liquid  in  the  tube  makes  possible  such  a  fluctuation 
in  the  tube  that  it  is  easier  to  determine  variations 
of  a  ten-thousandth  of  an  inch  with  this  instrument 
than  it  is  to  discern  a  thousandth  with  most  other 
measuring  instruments.  The  chamber,  A,  is  provided 
with  a  thread  and  micrometer  index  and  a  pointer  on 


PROFILE  AND  INDICATING  GAUGES  383 


the  upper  surface,  as  indicated,  to  show  thousandths  of 
an  inch.  This  portion  of  the  instrument  is  made  for 
the  purpose  of  obtaining  rough  adjustments;  but  it 
is  not  used  after  the  instrument  has  once  been  set 
to  the  size  desired.  The  carrier,  F,  is  furnished  with 
a  scale,  G,  and  three  adjustable  pointers,  H,  J,  and  K. 
The  upper  two  of  these  pointers  are  so  arranged  that 
they  can  be  set  to  indicate  the  tolerance  limit  between 
which  it  is  desired  to  keep  the  work  when  gauging. 
The  lower  pointer,  K,  is  set  to  the  normal  level  of  the 
fluid  in  the  glass  tube,  C,  so  as  to  compensate  for  any 
fluctuations  from  changes  in  temperature.  The  in- 
strument is  roughly  set  to  the  size  desired  by  means 


flO.  156-A.    FBESTWIGII  GAUGE  USED  IN  GAUGING  A  PISTON 


TOOLS  AND  PATTERNS 


of  the  rack,  M,  and  the  pinion,  N,  on  the  pillar,  0,  to 
suit  the  piece  which  is  to  be  ganged.  The  clamping 
screw  is  then  tightened,  and  the  final  adjustment  is 
made  by  the  micrometer  dial,  A,  to  a  standard  gauge 
or  a  piece  of  the  given  dimension. 

In  the  illustration,  a  piston  wrist  pin,  X,  is  being 
gauged,  a  small  special  angle  plate  being  set  on  top 
of  the  anvil,  E,  for  this  purpose,  as  clearly  indicated. 
It  is  evident  that  a  reading  can  be  taken  on  a  pin  of 
this  kind  by  simply  pushing  it  along  and  noting  any 
fluctuation  in  the  column  of  liquid,  C. 

Referring  to  Figure  156- A,  the  same  type  of  gauge 


m.  156-B.  raESTWicH  gauge  used  fob  inspection  of 

TOBEAD  GAUGES 


PBOFIIil  AND  INDICATING  GAUGES  385 


is  shown  applied  to  the  measurement  of  an  auto- 
mobile piston.  In  this  case  it  will  be  noted  that  the 
base  of  the  gauge  is  furnished  with  a  special  block, 
S,  and  that  a  different  indicating  point,  R,  is  used. 

In  testing  a  thread  gauge,  such  as  that  shown  in 
Figure  156-B,  another  application  of  this  most  useful 
gauge  is  found.  In  this  case  the  indication  point  is 
of  special  form,  permitting  the  *Hhree-wire  system" 
from  the  fixed  diameter  to  be  used.  It  will  be  seen 
that  with  this  improvement,  thread  gauges  or  work 
of  similar  character  can  be  determined  with  the 
utmost  nicety  and  tl^at  the  most  approved  system  of 
gauging  from  the  pitch  diameter  can  be  adopted. 
This  gauge  can  be  applied  to  many  other  varieties  of 
special  work,  and  its  sensitiveness  and  facilities  for 
quick  and  accurate  reading  make  it  invaluable  to  the 
progressive  manufacturer. 

Flush-Pin  Gauges.— The  flush-pin  gauge  is  with- 
out doubt  the  simplest  type  of  gauge  based  on  the 
indicating  principle.  Several  applications  can  be 
made  of  this  principle,  one  of  the  most  useful  of  these 
being  the  measuring  of  depths  or  shoulders. 

Flush-pin  gauges  usually  consist  of  a  base  or  holder 
of  some  sort  in  which  one  or  more  pins  are  inserted 
so  as  to  form  a  diding  fit  in  their  bearings.  The  pins 
are  made  of  correct  length  for  gauging  a  given  sur- 
face,  the  limit  being  determined  by  noting  the  amount 
of  projection  of  ttie  end  of  the  pin  beyond  the  end 
of  the  gauge  itself. 

As  an  example,  let  us  take  the  flush-pin  depth- 
gauge  shown  in  Figure  157.  In  this  case,  the  work, 
A,  is  placed  on  a  surface  plate  and  the  gauge  is  used 


TOOLS  AND  PATTKRNS 


f 


Surfacm  .Pfofe^ 

•  * 


no.  157.    FLUSH-PIN  DEPTH  GAUGE 

to  determine  the  correct  distance,  B.  The  gauge 
itself  consists  of  a  holder,  C,  through  which  the 
gauge  pin,  D,  works,  a  small  retaining  pin  being  used 
to  prevent  the  pin  from  falling  out  when  not  in  use. 
The  end  of  the  gauge  pin  is  cut  away  to  the  center 
line  to  show  the  amount  of  tolerance  allowed  in 
manufacturing  the  work.  In  using  the  gauge  the  in- 
spector simply  notes  that  the  shoulder  on  the  pin  is 
lower  than  the  finished  surface  on  the  holder  and  that 
the  end  of  the  pin  does  not  go  below  the  shoulder. 
This  indicates  that  the  work  has  been  machined 
within  the  desired  tolerance. 
Gauges  of  this  kind  axe  not  suitable  for  work 


PBOFILl  AND  INDICATINa  GAUGES  387 

within  very  close  limits.  From  0.003  to  0.005  inijh  is 
as  close  as  this  type  of  gauge  can  be  used  to  advan- 
tage. When  work  permits  a  variation  of  1/64  to  1/32 
inch,  gauges  of  this  kind  are  frequently  used,  but  for 
the  closer  work  they  are  by  no  means  to  be  recom- 
mended. They  can  be  adapted,  however,  to  fine  read- 
ings by  using  an  indicator  to  act  on  the  end  of  the 
pin.  This  indicator  can  either  be  of  the  dial  type, 
applied  by  mounting  it  on  a  suitable  holder,  or  it  can 
be  a  simple  pointer  pivoted  in  such  a  way  as  to 
provide  a  large  ratio  of  movement  at  the  end  of  the 
pointer. 

Referring  to  Figure  158,  let  us  suppose  that  the 
push  pin,  A,  in  the  upper  sketch,  is  in  contact  with 
the  work  at  the  end,  B,  and  that  variations  to 
0.001  inch  are  to  be  noted.  If  the  short  end  of  the 
pointer  has  a  fulcrum  %  inch  from  the  bearing,  C,  on 


177 

37177 


Oraduafhns  0.040'''^'- 
apart  /feadinq  Q/OOr  ^ 


apart,  ffeaamq  wvt 


,'Work 
vhnr 


A  'f\t$h  Bh 
.  .'Work 


wo.  158.    FWJSH-Pm  GAUGE  lOT  PRECISE  WCMBK 


388  TOOLS  AND  PATTERNS 

the  end  of  the  pin,  and  the  pointer  is  five  inches  long, 
then  the  ratio  of  multiplication  will  be  as  %  is  to  5  or 
as  1  is  to  40.  Therefore,  if  the  graduations  on  the 
arm  or  scale  are  cut  0.040  inch  apart,  a  variation  of 
the  pointer  on  one  of  these  divisions  will  indicate 
0.001-inch  variation  on  the  push  pin. 

Application  of  this  principle  can  be  made  to  many 
forms  of  gauges  requiring  a  reading  closer  than  that 
given  by  the  ordinary  flush-pin  type.  Still  closer  in- 
dications can  be  obtained  by  multiplying  the  levers, 
as  shown  in  the  lower  portion  of  the  diagram.  One 
lever,  working  on  another,  F,  will  obtain  a  larger 
ratio. 

Flush-Pin  Gauge  for  Tapered  Shafts.— When  a 
tapered  shaft  is  close  to  a  shoulder,  as  in  the  case 
shown  in  Figure  159,  it  is  difficult  to  gauge  the  taper 
as  to  its  position.  In  such  cases,  the  flush  pin,  B, 
can  be  arranged  so  as  to  push  the  gauge  on  to  the 
shaft  until  the  pin  strikes  the  shoulder,  A,  on  the 
work,  indicating  the  limit  when  the  pin  protrudes 


no.  159.    FI^DSH-PIN  OAUOE  WGR  TAFERED  SHAFTS 


PROFILE  AND  INDICATING  GAUGIS  389 

through  the  gauge  at  C.  Thi-s  pin  is  shouldered  to 
indicate  the  permissible  limit  of  error  similar  to  that 
shown  in  Figure  157.  Gauges  of  this  kind  can  also 
be  used  for  determining  shoulder  distances  on  straight 
or  taper  shafts. 

Flush-Pin  Gauge  for  Contours. — ^In  some  instances 
it  is  desirable  to  gauge  one  or  two  points  with  con- 
siderable accuracy  and  other  points  not  nearly  as 
closely.  Take,  as  an  example,  the  work  shown  in 
Figure  160.    In  this,  case,  the  length  of  the  work 


WG.  160.    FLUSH-PIN  GAUGE  FOB  CONTOURS 


between  the  points  F  and  G,  is  not  of  the  greatest 
importance,  but  the  irregular  portions  at  B  and  C 
must  not  be  above  a  certain  dimension  and  can  be 
permitted  to  be  under  the  dimension  by  0.005  to 
0.010  inch.  The  gauge  in  this  case  consists  of  a 
block,  L,  on  which  the  pins,  G,  P,  D,  and  E,  are 
carefully  set  and  against  which  the  piece  locates.  Two 
flush  pins,  at  H  and  K,  are  cut  away  on  the  end  to  show 
the  amount  of  the  tolerance  permitted.  It  will  be 
seen,  then,  that  as  the  work  is  placed  in  the  gauging 


390 


TOOLS  AND  PATTEBNS 


Ground. 


WMtC 


^  I 


no.  161.    DOUBLE  FLUSH-PIN  GAUGE 


fixture  these  two  pins,  H  and  K„  can  be  moved  up 
against  the  points  B  and  C,  and  the  inspector  can 
easily  determine  whether  the  projection  of  the  end  of 
the  flush  pin  is  too  great  or  not.  In  this  way  the 
desired  eontaar  of  the  work  can  be  kept  within  the 
required  limit.  Applications  of  this  principle  may  be 
made  to  many  other  kinds  of  work  where  it  is  neces- 
sary to  keep  a  certain  portion  within  a  specified  tol- 
erance. 

Flush-Pin  Depth-Ctonge  for  Indicating  Two  Sur- 
faces Simidtaneously. — ^Another  type  of  flush-pin 
gauge  for  use  on  two  surfaces  at  the  same  time  is 
shown  in  Figure  161.  This  gauge  is  made  up  some- ; 
what  differently  from  the  others,  as  the  pins  are 
made  of  flat  stock  and  the  holder  is  composed  of  two 
ttr-  side  pieces,  with  fillers  between  them,  the  two  side 
pieces,  D,  and  the  fillers,  E,  being  riveted  together  as 
indicated.  The  pins,  A  and  B,  indicate  different 
depths  on  the  fly-wheel  casting,  C,  and  the  limits  are 
shown  by  the  shoulders  on  the  pins,  as  indicated  at 
FandG. 


PIOFIUJ  AND  INDICATING  GAUGES  391 


Where  the  work  is  large,  as  indicated  in  the  illus- 
tration, a  gauge  of  this  kind  may  be  preferred  to  one 
made  of  a  solid  piece  of  bar  stock  with  holes  drilled 
and  reamed  for  the  pins.  It  is  somewhat  lighter  m 
construction  and,  although  no  cheaper  to  manufac- 
ture, it  is  a  trifle  more  convenient  to  handle.  Its 
operation  is  similar  to  the  flush-pin  gauges  previously 
described. 

In  making  a  gauge  of  this  kind,  the  various  parts 
are  hardened  and  are  lapped  to  a  finish.  Suitable 
retaining  pins  are  inserted  so  that  the  gauge  pins  wiU 
not  be  lost  when  the  instrument  is  not  in  use. 

Indicator  Ga;age  for  Testing  Alignment  of  Con- 
necting-Rod  Bearings.— The  parallelism  and  align- 
ment of  the  connecting-rod  bearings  of  an  automobile 
motor  is  exeeedingly  important.  It  is  not  enough  to 
know  that  the  alignment  of  the  bearings  may  be  in- 
correct, but  the  amount  and  direction  of  variation 
must  also  be  known.  In  order  to  determine  these 
two  points  it  is  necessary  to  use  a  gauge  based  on 
the  indicating  principle. 

An  excellent  type  of  gauge  for  this  purpose  is  shown 
in  Figure  162.  The  connecting  rod,  A,  has  been  pre- 
viously finished  in  all  of  its  dimensions,  and  is  sup- 
posed to  be  correct  and  ready  for  the  final  inspec- 
tion. Previous  to  placing  the  work  in  the  gauge,  it 
is  fitted  with  the  special  pins,  B  and  C,  hardened 
and  ground  to  size,  and  fitting  closely  in  the  bear- 
ings  at  each  end  of  the  connecting  rod.  After  the 
work  has  been  supplied  with  these  two  pieces  it  is 
placed  in  the  fixture,  T,  in  such  manner  that  the  large 
end  of  the  connecting  rod  lies  between  the  finished 


392 


TOOLS  AND  PATTERNS 


PlOPILl  AND  INDICATING  dAUGBB  393 


surfaces,  0,  on  the  fixtures  and  the  pins  at  B  and  C 
rest  on  the  hardened  pins,  D  and  F,  at  the  large  and 
small  ends  of  the  fixture  respectively.  When  the 
work  is  placed  in  position  tim  spring  pins,  N,  hold  it 
liftpmly  against  the  hardened  pins,  E,  the  pins,  N,  heing 
carefully  adjusted  so  as  to  be  perpendicular  to  the 
center  line  of  the  work. 

At  the  smaller  end  of  the  piece  4here  is  a  fixed  pin. 
F,  and,  on  the  opposite  side,  a  pin,  G,  with  an  adjust- 
able knurled  head  and  supported  by  the  coil  spring, 
H,  in  the  body  of  the  fixture.  One  side  of  the  spring 
pin  is  slotted  at  K  to  receive  the  end  of  the  indicator, 
L.  This  indicator  works  on  a  scale,  M,  reading  to 
.001  inch.  It  can  be  seen,  therefore,  that  any  vari- 
ation in  alignment  of  the  connecting-rod  bearings 
will  be  indicated  by  this  pointer  if  the  holes  are  not 
parallel  in  the  direction  indicated. 

Assuming  that  a  discrepancy  has  been  found  in  lie 
alignment,  a  suitable  clamp  can  be  placed  on  the 
piece  while  it  is  still  in  the  fixture  and  it  can  be 
twisted  until  the  alignment  is  correct.  Having 
straightened  out  the  alignment  in  this  direction,  it 
is  then  necessary  to  gauge  the  work  in  another  posi- 
tion. For  this  purpose  thMiMi  P,  bearing  a  dial  in- 
dicator, S,  is  mounted  in  bearings,  Q  and  B,  these 
bearings  being  put  on  a  line  with  the  center  line  of 
the  work.  An  indication  of  the  parallelism  of  the 
shaft,  C,  with  that  of  the  other  end,  B,  can  easily  be 
determined  by  swingmg  the  mdicatmg  gauge,  S,4tMMni 
one  side  to  the  other  of  the  shaft,  C,  and  noting 
whether  there  is  any  variation  in  the  reading  of  the 
dial  when  this  is  done.    The  indicator  should  read 


I 


I 


396 


TOOLS  AND  PATTERNS 


the  same  on  each  side  of  the  shaft  if  it  is  perfectly 
parallel  with  the  other  end. 

Applications  of  this  type  of  gauge  may  be  made  to 
many  kinds  of  work.  It  is  possible  to  use  either  the 
dial  indicator,  as  shown  in  this  instance,  or  multiply- 
ing levers  to  indicate  the  amount  of  variation  in  the 
work.  This  particular  gauge  was  designed  by  me  on 
some  work  for  the  Russian  government 

Special  Indicating  Oauge  for  an  Automobile  Cam 
Shaft— An  automobile  part  requiring  great  care  m 
gauging  is  the  cam  shaft.  A  special  indicating  gauge 
designed  for  such  use  is  shown  in  elevation  in  Figure 
163  and  in  plan  in  Figure  163-A.  In  this  work  the 
shape  of  the  cam  and  the  amount  of  throw  are  the 
imiK>rtant  points  to  be  inspected.  Usually  the  amount 
of  throw  of  the  cam  is  not  permitted  to  vary  more 
than  0.003  inch;  some  manufacturers  hold  their  work 
within  tolerances  even  closer  than  this. 

In  the  cam  shaft,  shown  at  A,  the  cams  indicated 
at  D,  D,  D,  have  been  forged  integral  with  the  shaft 
and  ground  to  the  desired  shape.  An  essential  point 
connected  with  the  form  and  throw  of  the  cams  is 
their  location  with  respect  to  each  other  and  also  in 
relation  to  the  key  way  on  the  tapered  end  of  the  shaft 
at  B.  It  follows,  therefore,  that  the  work  should  be 
located  from  this  keyway  in  gauging  the  cam.  The 
fiiinre  itself  consists  of  a  base  plate,  K,  which  has 
been  carefully  scraped  to  a  fine  finish  on*  the  surface. 
On  this  base  plate  three  bearings,  E,  are  set,  which  fit 
the  outside  diameter  of  the  cam  shaft.  In  gauging 
the  work  the  shaft  is  laid  in  these  three  bearings  and 
swinging  clamps  are  pulled  down  on  top  of  the  shaft 


PROFILE  AND  INDICATING  GAUGES  397 


by  means  of  the  handles  shown  at  F.  As  these 
handles  are  pulled  down,  the  detent  pins,  H,  snap  into 
place  in  a  conical  hole  in  the  side  of  the  lever,  and 
the  spring  plungers  in  the  center  of  the  swinging 
clamps,  as  shown  at  G,  bear  down  on  the  cam  shaft 
and  hold  it  firmly  in  place  in  the  bearings,  E. 
Although  these  spring  pins  hold  the  cam  shaft  firmly 
in  place  they  do  not  prevent  its  rotation.  After  the 
piece  has  been  set  into  place,  the  finger  lever,  K,  is 
pulled  down  until  the  work  can  be  revolved  suffi- 
ciently to  permit  the  locater  to  enter  the  keyway  at 
B.   The  work  is  now  set  ready  for  gauging. 

Let  us  assume  that  the  work  has  been  placed  in 
position  and  that  everything  is  ready  to  indicate  the 
piece.  ^  It  will  be  noted  that  the  block,  L,  is  fastened 
to  the. bed  plate  of  the  fixture  and  that  the  finger 
lever,  E,  is  contained  in  a  sliding  cylindrical  piece 
held  in  position  by  an  internal  spring.  At  the  end  of 
the  shaft,  M  (which  works  in  a  hardened  bushing  on 
the  inside  of  the  block,  L),  a  dial  plate,  0,  is  keyed 
in  the  correct  relation  to  the  finger  lever  and  keyway 
at  B  and  B.  This  dial  plate  contains  four  tapered 
bushings  in  proper  relation  to  the  keyway,  B,  and  the 
work  can  be  indexed  by  pulling  out  the  taper  pin,  P, 
and  turning  tie  knurled  hand-wheel,  Q,  for  indicating 
the  various  cams.  To  indicate  the  throw  of  the  cam, 
a  special  gauge — set  on  the  stand,  S,  and  having  three 
feet  of  hardened  steel,  as  shown  at  T,  and  an  upper 
arm  with  indicating  points  at  U  and  V  for  the 
**go"  and  "not  go**  limit  of  the  throw  of  the  cam^ — 
can  be  slid  along  the  surface  of  the  plate  until  the 
^'go"  and  ^^not  go''  points  on  the  gauge  come  in  con- 


TOOLS  AND  PATTBRNS 


PEOFIIjB  and  INDICATINa  GAUGES  399 


tact  with  the  cam,  thus  determining  whether  the 
throw  is  within  the  desired  limits  or  not.  After  these 
points  have  been  determined,  the  indicating  dial  l« 
revolved  and  the  next  cam  in  rotation  is  similarly 
tested. 

The  oontonr  or  shape  of  the  cam  is  ganged  by 
means  of  the  block,  W,  which  has  a  steel  plate  at  X, 
formed  to  the  contour  of  the  cam.  It  is  obvious  that 
this  gauge  is  also  moved  along  on  the  surface  of  the 
plate  until  it  comes  in  contact  with  the  cam  so  that  a 
comparison  €an  be  easily  made  by  the  inspector. 

After  the  shaft  has  been  completely  tested,  the 
entire  mechanism  of  the  indexing  head  is  pulled  away 
from  the  tapered  end  of  the  shaft  until  the  lever,  M, 
drops  down  into  the  recess  on  the  shaft  prepared  for 
it.  This  holds  the  mechanism  far  enough  back  so 
that  the  cam  shaft  can  be  removed  without  difficulty. 
A  gauge  of  this  kind  is  somewhat  expensive,  but  the 
results  obtained  by  its  use  are  most  excellent. 

Feeler  Gauge  for  an  Automobile  Crajik  Shaft.— A 

limit  gauge,  rather  peculiar  in  its  character  as  it  is 
nopwally  an  maicatmg  gauge  and  yet  ennMHI^ 
pended  upon  to  hold  the  work  within  the  prescribed 
limits  of  accuracy,  is  the  crank  shaft  gauge  shown  in 
Figure  164.  This  instrument  is  used  to  determine  the 
widths  of  the  various  bearings  on  the  crank  shaft 
and  their  relations  to  each  other.  One  of  the  features 
of  this  gauge  is  that  it  can  be  used  on  the  work 
while  in  process — ^it  is  not  Becei|||||^^  until  after 
the  crank  shaft  has  been  rem^WKt  the  machine 
before  testing  it  for  accuracy. 
The  gauge  itself  consists  of  a  single  hardened  and 


400 


TOOLS  AND  PATTEBNS 


ground  shaft,  D,  having  at  one  end  a  templet  plate, 
E,  which  fits  the  center  bearing  of  the  crank  shaft 
and  is  prevented  from  moving  sideways  by  means  of 
the  plate,  C,  which  is  ent  ont  to  fit  the  bearing,  as 
clearly  shown  in  the  end  view.  The  other  end  of  the 
gauge  is  also  provided  with  a  plate,  cut  out  in  like 
manner  so  that  the  operator  may  steady  the  gauge  on 
the  work  and  that  it  may  have  a  correct  location  in  re- 
lation to  the  axis  of  the  work.  In  order  to  prevent  the 
gauge  from  falling  over  sideways  while  the  various 
bearings  are  being  tested,  a  piece  of  sheet  steel,  M,  is 
fastened  to  the  shaft  as  indicated. 

Let  it  be  assumed  that  the  inspector  is  ready  to 
test  the  crank  shaft  and  that  the  gauge  has  been 
placed  in  position.  It  will  be  seen  that  the  bushings 
lying  between  the  spacing  collars  H  and  K,  have  each 
two  plates  or  fingers,  F  and  and  6  and  G\  located 
one  on  each  side  of  the  bushings.  Also  the  bushing 
at  the  end  of  the  crank  shaft  and  between  the  col- 
lars K  and  M  has  also  a  pair  of  feelers,  L  and  L*.  In 
testing  the  work,  the  feelers  at  these  various  points 
are  swung  by  the  operator's  fingers  between  the  bear- 
ings. If  the  first  feeler  goes  through  without  diffi- 
culty and  the  second  does  not,  the  inspector  is  ready 
to  pass  the  work.  After  one  end  of  the  crank  shaft 
has  been  tested  the  gauge  is  reversed  and  the  other 
end  is  tested  in  a  like  miKnner,  using  the  center  bear- 
ing as  the  gauging  point  in  each  instance.  After  the 
crank  shaft  has  been  gauged  in  this  way,  it  is  abso- 
lutely certain  that  all  the  crank  pins  and  bearings  are 
in  correct  relation  to  each  other  within  the  prescribed 
limits* 


PKOFILl  AND  INDICATING  aAUGES 


401 


Although  this  type  of  gauge  is  somewhat  out  of  the 
ordinary,  it  has  proved  successful  in  this  kind  of 
work.  It  is  obvious  that  the  greatest  care  must  be 
used  in  making  the  instrument  so  that  the  various 
parts  may  have  no  more  freedom  than  is  absolutely 
necessary. 

Electrical  Contact  Gauge  for  Cams.— The  use  of 

electrical  contact  for  determining  variations  within 
certain  limits  is  well  shown  in  Figure  165.  Here,  the 


WIQ,  165.    ELECTRICAL  CONTACT  GAUGE 


work,  A,  which  is  to  be  tested,  is  a  cam,  the  throw  of 
which  must  be  held  within  certain  limits  as  in  pre- 
vious instances.  In  this  case,  however,  the  cams  are 
not  on  a  shaft,  but  are  separate  and  can  be  handled 
on  a  much  smaller  and  simpler  type  of  fixture. 

The  work.  A,  is  placed  on  a  stud  (not  shown),  the 
stud  being  located  in  the  fixture  plate.  The  gauge 
is  so  arranged  that  if  the  throw  of  the  cam  is  cor- 
rect, a  red  light  will  show  at  J;  while  if  the  throw 


402 


TOOLS  AND  PATTERNS 


of  the  earn  is  too  great,  the  Ml,  K,  will  riiig.  A 
reference  to  the  illnstration  will  show  that  a  hattery 
is  connected  with  the  screw,  F,  and  through  it  to  the 
tempered  spring,  E.  A  multiplying  lever,  C,  is 
pivoted  at  B,  and  acts  on  the  push  pin,  D,  which  in 
turn  pushes  up  the  flat  spring,  E,  until  it  is  in  <}oii- 
tact  with  the  adjustable  screw,  G.  This  completes  an 
electrical  circuit  through  the  wiring  indicated  by  the 
clotted  line,  and  lights  the  red  light  at  J.  If  the 
throw  of  the  cam  is  too  great,  the  push  pin,  D,  forces 
the  spring,  E,  up  further  until  it  touches  the  other 
screw,  H,  which  also  completes  an  electrical  circuit 
and  rings  the  bell  at  K.  It  must  be  understood  that 
this  is  only  a  diagramatic  illustration  of  the  prin- 
ciples applied,  and  that  various  applications  suitable 
to  the  particular  piece  of  work  which  is  to  be  gauged 
can  be  conveniently  made. 

Profile  Inspection  Oange. — On  certain  classes  of 
work  the  profile  of  the  piece  must  be  kept  within 
certain  limits.  It  is  not  always  possible  or  conve- 
nient to  make  up  a  receiver  gauge  for  this  purpose 
and  even  when  one  is  used,  the  results  obtained  do 
not  show  up  the  variations  markedly  enough. 

The  tise  of  the  ordinate  principle  can  be  employed, 
as  shown  in  the  Mgnre  166,  in  a  case  of  this  kind. 
This  system  of  gauging  leaves  nothing  to  be  desired 
where  it  is  needful  to  inspect  for  accuracy  and  to  de- 
termine, at  the  same  time,  the  variation  in  the  con- 
tour of  the  work.  This  gauge  consists,  first,  of  a  sur- 
face plate,  A,  which  has  been  carefully  scraped  to  a 
plain  surface.  On  this  plate  a  master-gauge  piece,  X, 
is  placed  and  fastened  securely  in  position,  and  is 


PEOFILE  AND  INDICATING  GAUGES  403 


FIG.  166.    PEOFHiE  INSPECTION  GAUGE 

furnished  with  two  dowels,  D  and  B,  on  which  the 
piece  to  be  gauged  is  located.  A  dial  indicator,  F,  is 
mounted  on  a  special  block,  C,  and  has  a  hardened 
point,  G,  directly  under  the  gauge  or  indicator  point 
on  the  dial.  Before  using  the  gauge  it  is  moved  over 
to  the  plate,  B,  and  the  dial  is  set  at  0,  the  pin  then 
being  in  contact  with  the  perpendicular  side  of  the 
Hock,  B.  After  the  gauge  point  has  once  been  set  in 
line  and  the  indicator  turned  around  so  that  the  dial 
around  the  work  to  the  various  lines  shown  until  the 
lines  on  the  indicator  correspond  to  the  lines  on  the 
base  plate,  A.  A  reading  can  then  he  taken,  and  if 
the  pointer  does  not  show  variation  greater  than  that 
marked  on  the  plate  at  the  point  where  the  reading 
is  being  taken,  it  may  he  safely  assumed  that  the 
work  is  within  the  limits  prescribed.  The  system  of 
jrauging  can  he  applied  to  many  forms  of  work  which 
require  a  careful  inspection  of  the  contour  and  where 


TOOLS  AND  PATTERNS 


WG.  167.    GAUGE  FOB  DETERMINING  CONCENTRICITY 


it  is  necessary  to  know  kow  much  variation  there  is 
at  various  points. 
Oonooilrieity  Indicatiiig  Gauge  for  Higli-Ezplosive 

.Shells. — In  the  inspection  of  high-explosive  shells  the 
concentricity  of  the  exterior  surface  with  the  inside 
is  important  In  order  to  determine  this  rapidly  and 
without  difficulty,  the  gauge  shown  in  Figure  167 
was  designed.  This  is  a  very  simple  type  of  in- 
dicator gauge  and  the  principles  upon  which  it  is 
based  «re  applicable  to  many  other  forms.  The 
work,  A,  is  placed  on  the  fixture  and  is  located  by  the 
lower  end,  which  is  tapered,  at  C  and  also  by  means 
of  the  sliding  tapered  bushing  at  D.  This  latter 
bushing  is  supported  by  a  light  spring,  E,  in  order 
to  make  sure  that  there  is  a  contact  on  both  tapered 
bushings.  If  this  were  not  so  arranged,  it  might  he 
that  the  work  would  be  placed  in  position  and  located 
only  on  one  ^d,  which  would  cause  a  wobble  in  the 


PBOFILB  AND  INDICATING  OAUGES  405 


work  when  indicating.  The  standard  on  which  these 
two  bushings  are  located  may  be  revolved  in  the  fix- 
ture, and  the  work  can  be  turned  around  freely  by 
hand  when  in  position.  As  the  work  is  revolved,  the 
plunger,  F,  which  is  spring  controlled,  bears  against 
the  outside  of  the  casing  and  operates  the  indicating 
pointer,  pivoted  at  K,  and  has  a  fulcrum  at  G.  The 
lower  end  of  the  pointer  moves ,  along  the  arc  of  the 
graduated  scale,  H,  thus  showing  variations  in  the 
concentricity  of  the  work  according  to  the  amount  of 
multiplication  in  the  lev«r.  In  the  case  noted,  the 
multiplication  is  20  to  1,  as  this  is  amply  sufficient 
to  show  variations  in  the  concentricity  of  the  work. 
The  principle  shown  in  this  fixture  can  be  used  with 
an  indicating  dial;  it  is  simply  necessary  to  mount  the 
dial  indicator  in  some  way  on  the  fixture  so  that  the 
push  pin,  F,  will  operate  against  it. 

loliaiisson  Gauges.— Any  description  of  gauging 
systems  which  does  not  include  some  mention  of  the 
testing  blocks  originated  by  Mr.  C.  E.  Johansson 
would  be  incomplete,  although  the  system  is  well 
known  throughout  the  country.  Briefly  stated 
Johansson  standard  gauges  are  parallel-lapped  blocks, 
in  which  the  two  opposite  sides  of  each  block  are  per- 
fectly parallel  and  the  distance  between  them  is  equal 
to  the  size  marked  upon  the  block.  These  blocks  are 
furnished  in  a  number  of  sizes,  so  that  any  dimen- 
sion up  to  the  limit  of  the  various  blocks  can  be 
obtained  by  placing  the  surfaces  of  blocks  marked  to 
the  sizes  required  against  each  other  in  such  close 
contact  that  a  measurement  across  the  blocks  will 
give  absolutely  the  dimension  required. 


m 


TOOLS  AND  PATTERNS 


All  Johansson  standard-gauge  blocks  up  to  6  inches 
are  guaranteed  to  have  no  greater  error  than  0.00001 
imhf  that  is  1/100,000  part  of  an  ineh.  They  were 
originally  intended  for  nse  in  the  tool  room  only  for 
the  quick  and  accurate  laying  out  and  checking  of 
jigs  and  fixtures,  but  their  applications  have  become 
better  known  until  now  they  are  used  for  checking 
many  varieties  of  work.  The  gauge  blocks  are  made 
up  in  a  number  of  sets  to  suit  various  requirements. 
With  their  standard  holders  for  making  up  a  num- 
ber of  blocks  to  a  required  dimension,  they  can  be 
considered  as  a  valuable  adjunct  to  the  tool  room 
for  checking  dimensions,  limits,  gauges,  and  other 
work  requiring  extreme  accuracy.  A  lengthy  descrip- 
tion of  the  Johansson  system  of  gauging  is  unneces- 
sary, but  it  is  safe  to  say  that  no  manufacturer  who 
is  engaged  in  the  production  of  interchangeable  work 
or  any  kind  of  work  requiring  extreme  accuracy 
can  afford  to  be  without  a  set  of  these  gauging 
blocks. 


CHAPTER  XX? 


PATTERNS  . 

The  Use  of  Patterns.— A  casting  which  is  to  be 
machined  must  be  made  by  a  pattern.  The  simplest 
form  of  a  pattern  may  be  identical  in  sha.pe  and 
size  with  the  piece  which  is  to  be  made;  but,  on  the 
other  hand,  the  pattern  may  differ  quite  Widely, 
depending  upon  the  construction  of  the  piece,  the 
number  of  holes  in  it,  and  whether  it  has  ribs  or 
protuberances  of  different  kinds  which  may  necessi- 
tate that  it  be  made  up  to  provide  for  the  use  of 
core  boxes  or  core  prints.  Speaking  generally  a  pat- 
tern is  a  form  which  can  be  laid  in  damp  sand  or  some 
other  plastic  material  such  that  when  molten  metal  is 
poured  into  the  mold  the  desired  shape  will  be  re- 
produced in  metal.  Usually  the  outside  of  a  pattern 
has  the  general  form  of  the  piece  which  is  to  be 
moulded  and  differs  from  that  piece  only  in  the 
various  pieces  called  core  prints,  which  stick  out  from 
the  patterns  here  and  there  according  to  the  require- 
ments of  the  work. 

Patterns  are  usually  made  of  wood,  but  they  may 
also  be  made  of  metal,  rubber,  plaster,  and  occa- 
sionally of  other  materials.  Begardless  of  the  ma- 
terial used,  however,  the  pattern  itself  does  not  differ 
in  form  nor  is  the  result  obtained  greatly  different. 

m 


408 


TOOLS  AND  PATTERNS 


In  work  requiring  a  great  number  of  pieces  of  the 
same  kind,  metal  patterns  are  more  commonly  used, 
as  they  are  more  durable  and  will  stand  handling 
much  better  than  the  wooden.  For  work  that  is 
comparatively  small  and  involving  a  number  of 
pieces  of  the  same  kind,  a  number  of  small  metal  pat- 
terns can  be  made  np  and  arranged  in  the  mold 
about  a  **gate,"  so  that  a  great  many  castings  can 
be  made  at  one  time  in  the  one  mold. 

Wooden  jiatt^nis  and  metal  patterns  are  made  in 
practically  the  same  way,  the  difference  being  that  the 
metal  pattern  must  be  cut  and  worked  into  shape 
with  different  tools  than  those  used  on  the  wooden 
pattern  as  it  is  obvions  that  metal  cannot  be  cut 
properly  with  wood-working  tools.  Freqnently,  in 
the  making  of  a  metal  pattern,  a  wood  pattern  is 
first  made  which  is  a  little  larger  than  the  work  is 
to  be,  so  as  to  allow  for  finishing  and  also  for  jdirink- 
age,  and  a  casting  is  made  from  it  in  some  kind  of 
metal  which  can  be  conveniently  worked.  This  cast- 
ing is  then  used  for  the  metal  pattern  after  the  pat- 
tern maker  has  worked  it  np  to  the  desired  size. 

Form  of  Pattern.— In  making  a  casting,  the  first 
thing  for  the  pattern  maker  to  determine  is  just  how 
his  work  is  to  be  molded.  The  important  point  in 
this  connection  is  the  withdrawal  of  the  pattern  from 
the  sand  which  has  been  rammed  around  it.  If  the 
pattern  is  simple  in  character,  no  great  difficulty 
should  be  experienced  in  this  matter;  but  if  the  work 
has  a  number  of  bosses  or  Ings  and  is  of  a  peculiar 
shape,  the  matter  of  molding  must  be  carefully  con- 
sidered by  the  pattern  naaker  in  the  making  up  of 


PAffBENS 


409 


his  patterns.  Obviously,  it  is  necessary  for  the  pattern 
to  be  made  in  such  a  way  that  the  molder  can  with- 
draw it  from  the  sand  without  disturbing  the  im- 
pression which  the  pattern  has  created  in  the  sand 
The  pattern  maker  must  always  possess  foresight 
enough  to  make  provision  for  removing  the  pattern 
from  the  mold  after  the  sand  has  been  paxjked 

^"^MelJdd  of  Molding.— The  best  way  to  understand 
thoroughly  iust  how  a  pattern  is  molded  is  to  describe 
the  process  in  connection  with  a  simple  pattern,  sncn 
as  that  shown  in  Figure  168.  In  the  first  place 
it  must  be  recalled  that  the  fine  sand  used  for  mold- 
ing  is  moistened  slightly  so  that  it  will  hold  together 
in  the  flasks  into  which  it  is  pounded  or  rammed 
around  the  pattern.  These  flasks  are  of  various 
kinds,  but  in  their  simplest  form  they  are  boxes  open 
at  top  and  bottom  and  made  either  of  wood  or  metaL 
The  boxes  are  provided  with  lugs  on  the  sides 
through  which  dowel  pins  may  be  passed  so  that  two 
flasks  can  be  put  together  in  snch  ^  way  that  l^ey 
always  bear  the  same  relation  to  each  other.  They 
can  then  be  separated  and  replaced  at  will,  with  the 
-  assurance  that  the  parts  of  the  mold  m  the^  sand  will 
correspond.  The  upper  half  the  flask  is  t^^^^ 
-cope-  and  the  lower  half  is  the  -drag"  or  -nowel. 

limll  be  noted  that  the  pattern  shown  at  A  m 
Figure  168  is  what  may  be  called  a ''solid    or  one 

niece"  pattern  and  that  it  has  no  core  in  it.  It  may 
be  said  of  this  pattern,  therefore,  that  it  leaves  its 
own  core  in  the  sand  and  does  not  require  anything 
special  in  its  construction.   This  particular  piece  is 


410 


TOOLS  AND  PATTERNS 


an  exact  model  of  the  casting  which  it  will  produce 
and  is  a  good  example  of  the  simplest  form  of  mold- 
ing. The  shape  of  this  particular  piece  is  such  that 
file  angles  on  both  outside  and  inside  give  an  excel- 
lent draft,  permitting  the  work  to  be  removed  with- 
out disturbing  the  sand  in  any  degree.   When  the 


FIG.  168.    METHOD  OP  MOLDING  A  SIMPUS  PATTERN 


molder  prepares  to  mold  this  pattern  he  takes  a  large 
flat  board,  such  as  that  shown  at  C,  and  places  it  on 
Ms  bench.  On  this  board  he  places  the  pattern,  A, 
with  the  large  side  down;  over  it  he  puts  the  drag 
portion  of  the  flask.  He  then  sifts  or  riddles"  fine 
sand  all  over  the  surface  of  the  pattern  and  rams  it 
tightly.  After  this  has  been  done,  he  fills  the  re- 
mainder of  the  flask  with  coarse  sand  which  is  also 
ranomed  tightly,  just  filling  the  box  flush  to  the  top. 


PATTERNS 


411 


The  entire  box  is  then  turned  over  until  the  cope  side 
comes  upward,  as  shown  in  the  illustration.  The  ex- 
posed surface  is  now  sifted  or  covered  lightly  with 
parting  sand— that  is,  white  beach  or  river  sand. 
This  is  done  to  prevent  the  cope  side  of  the  flask  from 
sticking  to  the  drag.  The  cope  side  is  then  placed  in 
position  over  the  drag  and  the  entire  box  filled  with 
coarse  sand,  rammed  in.  Cope  and  drag  are  then 
separated,  the  pattern  carefully  removed  from  the 
mold,  the  cope  replaced,  and  the  flask  is  ready  for 
molding  or  is  set  aside  until  required. 

Cores  and  Owe  Boxes.— If  the  casting  to  be  made 
requires  a  hole  in  it  and,  because  of  the  shape  of  the 
pattern,  it  is  not  possible  to  place  the  pattern  in  the 
mold  (as  in  the  instance  noted)  in  such  a  way  as  to 
leave  a  pyramid  or  conical  portion  of  sand  in  the 
mold  that  will  prevent  the  metal  from  flowing  into 
that  part  and  thus  leave  a  hole  in  the  resulting  east- 
ing, it  will  be  necessary  to  make  a  separate  ''core." 
For  example,  in  Figure  169  a  separate  core  is  neces- 
sary  on  account  of  the  shoulder  on  the  inside  of  the 
work.    Thifi  requires  that  a  core  box  be  made 

specially  for  it. 

Cores  may  be  made  from  metal,  dry  sand,  or  green 
sand.  The  kind  illustrated  in  Figure  168  is  the  green 
sand  core  and  is  made  at  the  same  time  that  the 
mold  is  made.  There  are  occasional  instances  when 
a  green  sand  core  can  be  made  up  separately  and 
placed  in  the  mold,  but  these  cases  are  rather  rare 
and  need  not  be  considered  here.  Metal  cores  are 
chiefly  used  in  brass  work  or  other  work  in  which 
considerable  accuracy  is  required.  They  are  not  nsed 


412 


TOOLS  AND  PATTERNI 


JjSjm  C — — 


Core  Frmf 


I 


•  •  •  • . 

•  •  .  •  .1 


1 


I 


■ .  • . 


•  .  •  •  •  .  • 
'  •  •     •   •   '      .  • 


WG.  169.    MOLD  AND  PATTERN  SHOWING  USE  OF  BAKED  CCMHE 

in  molding  cast  iron.  The  most  common  form  is  the 
dry  sand  core.  This  is  made  from  a  fairly  coarse  sand 
mixed  with  «ome  binder  material  to  hold  it  together 
and  then  baked  nntO  perfectly  hard  and  thoroughly 
dry. 

Dry  sand  cores  are  molded  in  core  boxes  made  np 
to  the  shape  and  size  desired.  Core  boxes  are  nsnally 
made  of  wood  in  two  or  more  parts,  depending  some- 
what on  the  shape  of  the  core  itself.  The  making  of 
core  boxes  for  jyattems  is  fnlly  as  Important  as  the 
making  of  the  pattern  itself. 

After  the  core  box  has  been  made,  the  mixture  of 
sand,  with  the  binder  thoroughly  incorporated  in  it, 
13  plae^  in  tiie  core  box  until  it  is  filled  completely. 


PATTERNS 


413 


It  must  be  remembered  that  the  core  in  the  box  is 
stable,  but  when  removed  it  is  somewhat  delicate.  In 
some  cases,  then,  it  is  necessary  to  reinforce  the  core 
sand  by  means  of  rods  or  bars  of  different  shapes  to 
conform  to  the  size  of  the  core  and  its  contour.  After 
the  i5ore  box  has  been  filled,  the  core  is  removed,  laid 
on  a  plate,  and  placed  in  the  oven  in  order  to  dry 
out.  It  is  then  ready  for  use  in  the  mold,  having  first 
been  given  a  coating  of  blacking  with  a  composition 
of  plumbago  or  graphite,  in  order  that  the  molten 
metal  may  not  stick  to  the  core. 

Eeferring  to  the  pattern,  A,  Figure  169,  a  core 
print,  as  it  is  termed,  is  seen  at  each  end.  There  is 
a  taper  on  the  upper  of  these  prints,  for  it  is  on  the 
cope  side  of  the  mold  and  the  cope  could  not  readily 
be  removed  unless  this  part  of  the  print  were  made 
tapering.  Occasionally  the  tapered  end  of  the  core 
print  is  removable,  so  as  to  make  it  easier  for  the 
molder  to  do  his  work.  Otherwise  the  molder  will 
bore  a  hole  in  his  molding  board  to  accommodate  this 
end  of  the  print  when  ramming  up  the  pattern. 

Beferring  to  the  casting,  B,  shown  in  the  same  illus- 
tration, an  inside  recess  is  seen  of  such  a  form  that  it 
would  be  impossible  to  mold  the  work  from  a  pattern 
without  a.  separate  core.  Thereforei|||^^  is 
made  up  to  give  the  form  indicated  at  c7and  after 
the  pattern  A  has  been  rammed  in  the  mold,  this  core 
C  is  inserted  prior  to  the  molding  operation  as  in- 
dicated in  the  illustration.  When  the  metal  is  poured 
into  the  mold  it  will  flow  all  around  thi«  coJe  and 
into  the  depression  left  by  the  pattern  form,  thus  pro- 
ducing the  desired  shape.  After  the  iron  has  cooled 


414 


TOOLS  AND  PATTERNS 


and  the  mold  is  dumped^  the  core,  being  of  a  fragile 
nature,  can  easily  be  broken  up  and  knocked  out  of 
the  casting,  which  is  then  left  in  the  condition  shown 

atB. 

Two-Pari  Pattarn  and  Melliod  of  Molding.— The 

casting,  A,  Figure  170,  is  seen  to  have  flanges  at 
each  end  of  such  form  that  the  casting  could  not  be 
molded  in  the  same  manner  as  that  shown  by  Figure 
169.  In  work  of  this  kind  the  better  method  is  to  make 
up  a  two-part  pattern,  as  shown  at  B,  and  prepare 
to  mold  the  work  as  indicated  in  the  illustration.  It 
will  be  noted  that  this  two-part  pattern  is  separated 
on  the  center  line  and  that  there  is  a  dowel  pin,  C, 
at  each  end  of  the  pattern  so  that  the  two  parts  can 
be  placed  together  in  their  correct  relation  at  all 
times. 

In  molding,  one-half  of  the  pattern  is  laid  down  on 
the  molding  board  and  the  drag  portion  of  the  mold 
is  rammed  up  around  it.  The  mold  is  then  turned 
over  and  the  other  half  of  the  pattern  laid  on  to.  its 
fellow,  after  which  the  cope  side  of  the  mold  can 
be  rammed.  After  lifting  out  the  pattern  and  placing 
the  core  in  portion  as  noted,  the  work  is  ready  for 
molding.  ' 

Occasionally  in  cheap  pattern  work  it  may  not  he 
desirable  to  make  a  two-part  pattern.  When  this  is 
the  ease,  the  imtlhod  shown  in  the  lower  part  of  the 
illustration  can  be  used.  In  tMs,  the  pattern  is  made 
in  one  piece,  and  the  molder  lays  the  pattern  down 
on  his  molding  board  and  rams  up  the  mold  in  the 
drair  portion.  He  then  turns  over  the  drag,  as  indi- 
cated in  the  illustration,  cuts  down  the  slope,  D, 


PATTERNS 


415 


c 

LP 

u 

Pa /fern 


^•^^^:r^ll^:  •.v  J 


%         COPE:,'       'In jx. 


FIG.  170.    TWO  METHODS  OF  MOLDING  A  PATTERN  WITH  FLANGES 

Upper  figure  shows  the  split-pattern  method.   Lower  shows 

solid  pattern. 


with  his  molding  tool,  and  removes  the  sand  down  to 
the  center  line  of  the  pattern,  leaving  it  all  clear  and 
clean.  After  sifting  parting  sand  on  the  drag  portion 
of  the  mold,  he  places  the  cope  flask  in  position  and 
rams  this  up  also  until  it  takes  the  form  shown  in 
the  illustration.  The  cope  can  then  be  lifted  care- 
fully off  so  as  not  to  disturb  the  sand  which  is  hang- 
ing below  it,  and  the  pattern  can  be  removed  and  the 
core  inserted  as  in  the  previous  instance.  TMs 


TOOLS  AND  PATTEBNS 


method  of  moMing  is  seldom  used  unless  only  one  or 
two  castings  are  desired  from  a  certain  pattern,  for 
too  great  a  portion  of  the  molder's  time  is  taken  up 
than  the  work  warrants. 

Girviilar  Oovw  PatteriL— Figure  171  shows  a  some- 
what different  type  of  pattern.  Here  the  work  to  he 
produced  from  the  pattern  is  shown  at  A,  and  the 
method  of  molding  the  piece  is  indicated  in  the  lower 
portion  of  the  figure.  In  this  case  the  parting  line 
of  the  pattern  is  at  C;  there  is  a  projection  into  the 
cope  of  the  pattern  itself,  and  also  the  portion,  B, 
of  the  cope  extends  down  into  the  pattern.  To  use 
this  pattern  it  must  be  laid  down  on  the  molding 
board  and  a  suitable  recess  provided  for  the  flange 


no.  171.  ontcuLae  ooveb  pavcebn  showino  pabt  of  the 

MIXi>  IN  THE  OOFE  SIDE 


PATTERNS 


417 


portion  so  that  the  parting  line,  C,  will  lie  flat  on 
the  board.  The  sand  is  then  rammed  around  the 
pattern,  after  which  the  drag  is  turned  over  in  the 
usual  way  and  dusted  with  parting  sand.  The  cope 
is  now  placed  in  position  and  rammed  up,  the  sand 
being  forced  down  into  the  portion  B,  and  lifting  out 
as  the  cope  is  removed  so  that  the  part,  B,  remains 
hanging  from  the  cope  side  of  the  mold. 

Pattern  Requiring  a  Thrw-Part  Flaak.— In  some 
instances  it  is  necessary  to  mold  a  certain  kind  of 
pattern  in  a  flask  containing  more  than  two  parts. 
An  instance  of  this  kind  is  shown  in  Figure  172 
where  the  work.  A,  is  a  casting  having  four  ribs  and 
a  flange  at  each  end.  It  is  apparent  that  it  would  not 
be  possible  to  ram  sand  all  around  the  pattern  and 
then  be  able  to  remove  it  from  the  sand  without  dis- 
turbing  the  mold.  The  pattern  is  made  up,  therefore, 
in  the  form  shown  at  B,  the  usual  core  print  being 
applied  and  the  pattern  itself  being  arranged  so  that 
it  can  be  separated  along  the  line  X-T. 

The  process  in  molding  this  pattern  is  as  follows: 
The  large  flange  is  placed  on  the  molding  board,  the 

cheek"  of  the  three-part  flask  is  first  rammed  up  as 
far  as  -the  separation  of  the  pattern  X-Y,  the  cope 
being  then  placed  in  position  and  rammed  in  turn. 
Both  cope  and  cheek  are  then  turned  over  together 
on  to  the  molding  board  and  the  drag  side  is  com- 
pleted. In  removing  the  pattern,  one  part  is  drawn 
from  the  large  flange  side  and  the  other  from  the 
small  flange  side.  The  core  can  then  be  placed  in 
position  in  the  usual  way,  and  the  mold  is  ready  for 
pouring. 


418 


TOOiiS  AND  FATTEBNS 


MG.  172.  EXAMPLE  OF  MOLDING  A  FLANGED  AND  KIBBED  PATTERN 

IN  A  THREE-PART  YLASK. 


Other  Forms  of  Patterns.— It  is  not  necessary  to 

present  a  lengthy  discussion  of  the  various  forms  of 
patterns,  but  several  other  kinds  may  be  mentioned 
in  a  general  way  in  order  to  make  the  snbject  a  little 
clearer.  The  matter  of  loose  pieces  i-s  one  which  occa- 
sionally gives  the  pattern  maker  and  molder  more  or 
less  trouble.  For  instance,  in  making  a  casting  that 
has  a  number  of  lugs  or  bosses  on  it  of  such  a  kind 
that  they  could  not  be  readily  removed  from  the 
molds,  the  pieces  are  frequently  made  loose  with  a  pin 
in  them  to  permit  their  ready  removal.   In  molding 


PATTERNS 


419 


such  a  piece  of  work  the  pins  are  removed  from  the 
loose  pieces  before  the  pattern  is  taken  out  of  the 
mold;  the  pattern  can  then  be  removed  without  dis- 
turbing the  loose  pieces  which  can  be  taken  out  by 
the  molder 's  hands  afterwards. 

The  type  of  patterns  known  as  "sweep"  patterns 
should  also  be  mentioned.  These  are  used  for  circular 
work  when  a  very  cheap  pattern  is  desired.  They 
can  be  made  for  almost  any  kind  of  cylindrical  ring, 
and  if  made  in  sectional  form  to  take  up  a  certain 
portion  of  the  mold  desired,  this  part  of  the  pattern 
can  be  attached  to  a  radius  stick  pivoted  at  the  cen- 
ter of  the  mold  and  a  part  of  the  mold  rammed  up  at 
a  time.  After  one  section  of  the  mold  has  been  pre- 
pared in  this  way,  the  sweep  can  be  moved  around  to 
another  section  which  is  treated  in  like  manner. 

Skeleton  patterns  may  also  be  used  in  a  somewhat 
similar  way.  But  attention  should  be  called  to  the 
fact  that  each  of  these  types  just  mentioned  is  used 
for  the  purpose  of  economy  where  only  a  very  few 
eastings  are  to  be  made  from  any  one  pattern.  The 
skeleton  pattern  is  used  in  place  of  a  complete  pat- 
1  tern,  but  its  principal  claim  to  distinction  is  that  it 
can  be  made  up  cheaply  for  cylindrical  work.  While 
the  pattern  maker  saves  considerable  time  in  making 
either  a  skeleton  pattern  or  a  sweep,  the  molder,  how- 
ever, is  required  to  spend  very  much  more  time  in 
making  up  the  molds  than  he  would  do  if  he  were 
provided  with  the  proper  kind  of  pattern. 

Tools  for  Paittem  MaUiig.— The  tools  used  in  pat- 
tern making  are  much  the  same  as  those  used  by  any 
carpenter,  except  that  a  number  of  varieties  of  spe- 


420 


TOOLS  AND  PATTERNS 


ml  tools  are  required,  sucli  as  those  used  by  the 
cabinet-maker  and  wood-carver.  A  number  of  spe- 
cial machines  are  in  use  in  the  pattern  shop  in  order 
to  facilitate  the  work  of  pattern-making.  These  in- 
clude such  special  machines  as  the  core^box  machine, 
which  is  specially  designed  to  assist  in  cutting  out 
the  inside  work  in  a  core-box,  and  also  sand-paper- 
ing machines  of  the  disc  type  with  adjustable  tables 
to  permit  them  to  be  set  to  different  angles  for  the 
greater  convenience  of  the  pattern  maker.  Other 
tools  used  in  the  pattern  shop  are  the  circular  saw, 
the  band  saw,  the  hand  jointer  or  buzz  planer,  the 
mortiser,  and  the  shaving  machine.  Special  pattern- 
maker's  vises  might  also  be  mentioned,  which  are  so 
constructed  as  to  hold  the  work  in  any  desired  posi- 
tion withimt  injury.  The  tool-maker's  engine  lathe 
is  also  found  in  the  pattern  shop  and  is  largely  used. 
In  addition  to  all  the  above,  each  pattern  maker  has 
his  own  private  supply  of  hand  tools,  most  of  which 
have  been  made  up  by  himself  for  certain  kinds  of 
work  which  has  been  out  of  the  ordinary.  Aside  from 
these,  the  cabinet-maker's  or  carpenter's  kit  of  tools 
would  represent  general  usage. 


CHAPTER  XXVI 
PATTERN  BEGOBDS  AND  STORAGE 

Desirability  of  Pattern  Records. — ^Keeping  patterns 
after  they  are  made,  in  a  safe  and  readily  accessible 
place,  is  a  matter  that  has  deservedly  received  con- 
siderable attention  in  late  years.  Formerly,  the  boss 
pattern-maker  had  a  system  of  his  own;  he  located 
any  desired  pattern  in  from  ten  minutes  to  three  or 
four  days,  depending  on  his  memory  and  the  amount 
of  time  he  could  spare  in  looking  it  up. 

The  boss  pattern-maker  frequently  was,  and  still  is, 
a  man  who  had  held  the  position  for  a  number  of 
years  and  who  might  be  expected  to  know  what  a 
given  pattern  looked  like  and  where  it  was  likely  to  be 
found.  Memory  is  a  poor  thing  to  depend  on,  however, 
for  locating  anything,  and  the  results  from  the  sud- 
den death,  illness,  or  resignation  of  the  man  having 
this  store  of  knowledge  can  well  be  imagined.  Con- 
sider the  amount  of  time  consumed  by  the  boss  pat- 
tern-maker under  ordinary  circumstances  in  finding 
a  given  pattern  and  estimate  the  cost  of  finding  the 
pattern  under  these  conditions. 

However,  it  is  gratifying  to  note  the  progress 
made  in  this  respect  among  present-day  manufac- 
turers. Nearly  all  of  them  now-a-days  have  a  well- 
ventilated,   light,   and   convenient  pattern-storage 


422 


TOOLS  AND  PATTERNS 


building,  with  suitable  racks  or  compartments  in 
which  the  patterns  are  kept.  In  former  times  it  hap- 
pened not  infrequently  that  the  loft  (if  there  hap- 
pened to  be  one  above  the  pattern  shop)  was  utilized 
for  storage,  and  it  took  a  man  with  a  searchlight 
and  a  pair  of  good  eyes  some  time  to  find  what  he 
wanted. 

Quality  of  Patterns.— Before  going  into  the  matter 
of  pattern  storage  and  records,  I  should  like  to  say 
a  few  words  in  regard  to  economy  in  the  construction 
of  patterns;  for  it  is  always  a  good  plan  to  consider 
other  things  in  addition  to  the  first  cost  of  a  pattern, 
and  there  are  many  factors  affecting  the  construc- 
tion. 

It  is  obvious  that  the  number  of  pieces  to  be  made 
from  a  given  pattern  is  an  essential  factor  in  deter- 
mining the  character  of  the  pattern.  For  example, 
a  jig  or  fixture  pattern  is  usually  made  as  cheaply 
as  possible,  for  it  will  only  be  used  once  or  twice. 
Any  other  sort  of  pattern  for  a  special  machine  or 
mechanism,  which  will  be  used  for  only  one  or  two 
castings,  would  therefore  seem  to  come  under  the 
same  category,  but  here  other  factors  vitally  affect 
the  construction.  A  special  machine  may  be  de- 
signed for  use  in  a  manufacturer's  own  shop,  or  it 
may  be  sold  to  a  customer;  in  either  case  th^  appear- 
ance of  the  finished  machine  must  be  considered,  and 
therefore  the  pattern  should  be  well  filleted,  with 
comers  rounded,  and  finished  throughout  so  that  the 
castings  obtained  from  it  will  be  of  good  appearance. 

Speaking  generally,  it  is  not  necessary  or  even  de- 
sirable to  give  patterns  of  this  kind  a  high  finish 


PATTERN  BECOBDS  AND  STORAGE  423 


with  several  coats  of  varnish.  A  good  sandpaper 
finish  is  usually  sufficient,  although  a  coat  of  shellac 
is  a  very  good  protective  covering  that  may  preserve 
the  pattern  in  better  condition  than  if  it  were  left 
without  it,  in  the  event  that  other  castings  may  be 
wanted  at  a  later  date.  These  matters  are  generally 
left  to  the  judgment  of  the  pattern-maker  when  he  is 
instructed  by  the  foreman  as  to  the  kind  of  pattern 
wanted. 

Usually  in  making  a  pattern  for  a  single  castmg, 
the  warping  of  the  wood  from  which  it  is  made  and 
the  consequent  distortion  arising  therefrom  are  not 
taken  into  consideration,  so  that  if  another  casting 
is  desired  at  a  later  date,  it  may  easily  happen  that 
the  results  obtained  in  the  second  case  are  unsatis- 
factory. If  there  is  a  likelihood  of  a  pattern  being 
used  a  second  time,  provision  should  be  made  to  pre- 
vent undue  warping.  However,  attention  to  this  mat- 
ter should  not  permit  too  great  an  addition  to  the 
first  cost  of  the  pattern.  Judgment  should  be  used 
in  all  cases. 

Patterns  which  are  built  up  in  sections,  with  the 
grain  of  the  wood  running  in  opposite  directions,  are 
not  generally  desirable  for  single  casting  work  on 
account  of  the  first  cost  of  the  pattern;  but  when  the 
shape  of  the  work  is  such  that  there  is  strong  likeli- 
hood of  distortion,  the  pattern  should  be  made  sub- 
stantial  enough  to  counteract  any  tendencies  of  this 
kind. 

For  patterns  which  are  to  be  used  over  and  over 
again,  the  first  cost  should  jg||||||p5ondary  considera- 
tion. A  poorly  built  patter|||ii||:  o'ut  of  shape  and 


TOOIiS  AND  PATTERNS 


become  so  damaged  by  frequent  molding  that  it  will 
soon  need  to  be  replaced  by  another.  Of  course, 
when  the  size  of  the  work  will  permit  it,  and  the 
number  of  castings  to  be  made  warrants  the  expendi- 
ture,  a  metal  pattern  is  most  satisfactory.  The  cost 
of  a  metal  pattern,  however,  is  very  much  greater 
than  the  cost  of  one  made  of  wood,  so  that  it  is  un- 
economical to  use  metal  unless  a  great  many  pieces 
of  the  same  kind  are  to  be  cast  from  the  same  pat- 

M   

tern. 

In  machine-tool  patterns  there  is  always  a  pos- 
sibility of  a  change  in  design  of  the  machine.  This 
may  make  an  entirely  new  pattern  necessary,  and 
therefore  metal  patterns  shonld  be  rather  sparingly 
used  for  work  of  this  kind  because  of  their  expense 
and  the  likelihood  of  an  early  discard. 

Economy  in  Ctombination  Patterns. — In  the  making 
of  pnlleys  or  gears  with  spokes,  which  require  sev- 
eral pieces  of  the  same  diameter  but  with  different 
lengths  or  sizes  of  hubs,  considerable  economy  can 
be  effected  by  using  one  spider  and  ring  pattern  with 
loose  bub  pieces  of  different  lengths  and  diameters. 
A  combination  of  these  loose  hub  pieces  with  the 
spider  and  ring  will  meet  a  number  of  different  con- 
ditions. The  spiders  can  also  be  made  with  a  vary- 
ing nnmber  of  ^kes  and  the  pulley  rings  can  be 
made  in  different  widths  so  that  a  wide  variety  of 
castings  can  be  obtained.  Hubs  and  spiders  can  be 
so  made  as  to  be  interchangeable  one  with  another, 
so  that  with  only  a  few  complete  patterns  combina- 
tions of  all  kinds  can  be  quickly  and  satisfactorily 
effected. 


PATTERN  RECORDS  AND  STORAGE 


Gear  Molding  Machine.-Another  great  economy 
in  pattern  making  has  been  the  development  of  the 
gear  molding.   This  permits  a  special  pattern  to  be 
made  in  sectional  form  which  has  only  one  tooth 
space  on  the  rim  and  a  part  of  a  tooth  on  each  side 
instead  of  an  entire  pattern  of  a  gear  with  teeth  all 
around  it  more  or  less  accurately  spaced  a«oo^dmg 
to  the  skill  of  the  pattern  maker.   The  gear  molding 
machine  takes  the  sectional  pattern  and  molds  the 
remainder  of  the  teeth  far  more  accurately  than  is 
possible  in  any  other  way. 

Pattern  Records.-Having  considered  the  inakmg 
of  the  patterns  and  the  economies  which  can  be  put 
into  effect  in  their  construction,  let  us  see  how  we 
can  best  take  care  of  them  after  they  have  been 
made,  and  how  we  can  locate  them  when  wanted 
without  resorting  to  memory.    It  is  apparent  that 
any  record  for  patterns  must  be  based  on  the  method 
used  in  identifying  any  component  part  in  the  class 
of  work  being  manufactured.  Thus,  if  machine  tools 
are  being  made,  the  system  used  should  identify  the 
machine  by  number  or  name,  the  part  by  number  and 
name,  and  the  location  of  the  pattern  in  its  rack  in 
the  pattern  storage  building.    It  is  useful  also  to 
have  the  date  that  the  pattern  was  made,  its  cost, 
and  the  weight  of  casting  incorporated  in  the  index, 
together  with  information  regarding  core  boxes  and 
a  record  of  castings  made  with  date  of  order,  ete. 
Figure  173  shows  a  simple  index  card  that  is  ap- 
plicable in  recording  the  patterns  used  m  making 

machine  tools.  ,j  v,  i.i„j 

In  any  record  of  this  kind  the  cards  should  be  filed 


426 


TOOLS  AND  PATTERNS 


Machine  Na_/^..  Piece  No.„Z&L^  „ 

Naffiw  of  Hect— .5^&f^^±^-,   Location  EiiLtQ  

Patterns  /   Core  Boxes  ?  


Dale  Cast* (s  Ordorcd 

No. 

Whara  Ordarad 

Weight 

Prica 

Cost 

m.  ^. 

s 

/ff 

/  -  <r  -  /7 

JO 

3/70 

H 

3f 

ro 

Wm.  173.    PATTERN  STOBAGE  EEfXIRD  CARD 


under  tbe  number  of  the  maehine  itself  and  then 
numerically  by  piece  number.  A  cross  index  is  also 
valuable  in  which  the  parts  are  filed  alphabetically 
by  name,  but  this  index  need  only  be  nsed  when  the 
piece  number  is  not  known. 

It  is  evident  that  any  kind  of  a  pattern  storage 
index  must  be  arranged  according  to  the  require- 
ments of  the  particular  product,  but  adaptations  of 
the  foregoing  system  can  be  devised. 

Marking  the  Patterns. — ^Every  pattern  should  have 
a  number  fixed  to  it  so  positively  that  it  cannot  be- 
come lost  or  separated  from  the  pattern  itself.  An 
aluminum  plate  ¥dth  the  number  embossed  on  it  is 
very  excellent  for  this  purpose,  and  machines  adapted 
to  the  marking  or  stamping  of  these  plates  should 
form  a  part  of  every  pattern  shop  equipment.  These 


PATTERN  RECORDS  AND  STORAOB  m 

machines  are  simple,  reasonable  in  price,  and  do  not 
get  out  of  order  easily.  In  addition  to  the  number 
plate,  the  number  should  be  painted  on  the  pattern 
in  case  the  plate  should  be  knocked  off  and  lost.  It 
is  also  necessary  to  have  the  storage  location  plamly 
marked  on  the  pattern,  so  that  when  it  is  returned 
from  the  foundry  it  can  easily  be  put  m  its  proper 
place  without  reference  to  the  card  index. 

Storing  the  Patterns.— The  actual  method  used  m 
storing  patterns  is  dependent  upon  the  facilities  pro- 
vided or  available  for  the  pMHppIf  a  building  can 
be  used  for  this  storage,  it  sSouId  be  etiuipped  with 
steel  or  wooden  racks-preferably  steel-laid  out  in 
aisles  or  sections.  Each  section  can  be  given  a  letter 
and  each  shelf  a  number,  so  that  a  location  specihed 
as  F-21,  for  example,  would  mean  Section  F,  Shelf  21. 
This  can  be  further  subdivided  to  provide  for  small 
patterns  by  a  suitable  box  which  can  be  placed  on 
the  shelf  and  also  designated  by  a  number  or  letter, 
as  F-21-C,  which  would  indicate  Section  F,  Shell  il, 
Sox  C 

The  lighting  of  the  pattern  storage  building  is  im- 
portant If  the  building  can  be  lighted  by  ordinary 
daylight,  it  is  an  advantage;  but  if  daylight  is  not 
available,  good  artificial  lighting  should  be  provided, 
preferably  by  means  of  portable  incandescent  bulbs 
suitably  caged  and  having  long  cords  to  permit  lights 
to  be  carried  from  one  shelf  to  another  as  required. 

Another  point  which  should  be  mentioned  in  con- 
nection with  pattern  storage  is  that  the  building 
must  be  dry,  since  moisture  is  very  apt  to  affect  the 
glue  in  the  patterns  to  such  an  extent  that  it  may 


428 


TOOLS  AND  PATTERNS 


cause  them  to  fall  apart  and  give  an  endless  amonnt 
of  trouble. 

By  no  means  the  least  important  of  the  factors  in 
connection  with  pattern  storage  is  the  nature  of  the 
building  in  which  they  are  stored.  It  might  be  said 
that  above  all  buildings  in  the  plant,  this  should  be 
as  nearly  fireproof  as  possible.  One  can  readily 
imagine  the  havoc  cansed  to  any  plant  through  the 
loss  of  the  patterns  on  which  the  business  was  based. 
At  a  price,  buildings  and  machinery  can  be  readily 
replaced  in  fairly  short  order;  but  patterns,  which 
are  the  fruitd  of  years  of  development  and  upon  each 
of  which  large  sums  of  money,  in  many  cases,  have 
been  expended,  can  only  be  replaced,  if  ever,  by  an 
equal  expenditure  of  time  and  money.  In  other 
words,  it  is  possible  that  the  loss  or  destruction  of  the 
patterns  through  fire  might  result  in  the  total  failure 
of  the  business;  the  least  effect  is  a  more  or  less  pro- 
tracted delay  in  filling  orders. 

Many  of  the  patterns  themselves  are  highly  in- 
flammable; these  should  be  individually  guarded. 
Metal  patterns,  of  course,  suffer  little  danger  of  dam- 
age from  a  small  fire;  but  in  the  event  of  the  loss  of 
the  storage  building  by  fire,  even  they  would  be  dam- 
aged beyond  repair.  Too  great  stress,  therefore,  can- 
not be  placed  on  this  point,  and  in  far  too  many  cases 
it  is  a  factor  which  has  apparently  been  entirely 
overlooked. 


t  CHAPTER  XXVII 

CAEE  AND  STOEAGE  OF  CRUCIBLES 

Clay  Gmdbtes. — ^The  crucibles  used  for  melting 
small  quantities  of  metals  are  made  either  from  clay 
or  graphite.  In  the  steel  industry  crucibles  are  used 
extensively,  principally  in  the  manufacture  of  so- 
called  crucible  steel  Their  greatest  use,  however, 
is  in  brass  foundry  work,  and  the  graphite  form  is 
much  preferred  to  the  clay  on  account  of  its  greater 
durability. 

When  clay  crucibles  are  used,  a  high  grade  cl^iy 
is  mixed  with  about  5  per  cent  of  powdered  coke  and 
made  into  a  stiff  dough  or  paste  by  the  addition  of 
water.  The  mixture  is  then  thoroughly  worked  or 
kneaded  until  it  is  of  uniform  consistency,  after 
which  it  is  forced  into  a  mold  of  the  desired  shape 
by  means  of  a  plunger.  The  top  of  the  crucible  is 
then  formed  (after  removal  from  the  original  mold) 
by  forcing  over  it  another  die  of  conical  shape.  The 
formed  crucibles  are  then  allowed  to  dry  slowly  for  a 
few  days  without  the  aid  of  artificial  heat.  After  this 
preliminary  drying  they  are  placed  near  the  melting 
furnaces  for  final  drying  out. 

In  the  molding  operation  a  hole  is  left  in  the  bot- 
tom of  the  crucible,  through  which  a  pin  passes  to 
center  the  plunger  used  in  forcing  the  clay  into  the 

429 


430 


TOOLS  AND  FATTERNS 


mold.  This  hole  is  left  open  until  the  crucible  is 
placed  in  the  furnace,  and  is  closed  by  resting  it  on  a 
little  ciay  stand  in  the  furnace  and  throwing  a  little 
sand  into  the  hole.  This  sand  fuses  very  quickly  from 
the  heat,  effectively  stopping  the  hole  and  at  the 
same  time  cementing  the  crucible  to  the  stand  on 
which  it  rests. 

The  greatest  eare  is  nec^sary  in  handling  clay 
crucibles.  They  must  be  heated  very  slowly,  and 
must  be  re-charged  while  hot.  While  their  normal 
cost  is  not  high,  they  are  easily  broken  and  may 
cause  a  loss  in  metal  and  in  damage  to  the  furnace 
in  which  they  are  used  far  in  excess  of  the  value  of 
the  crucible. 

iSraidiite  Gnicibles. — Graphite  crucibles  have  many 
advantages  over  those  made  from  clay,  and  are  there- 
fore used  by  a  majority  of  manufacturers  in  this 
country.  They  will  stand  more  heats  and  rougher 
handling  than  clay  crucibles;  can  be  tested  for  cracks 
and  thickness  before  charging,  and  can  be  charged 
cold. 

Prior  to  the  war,  graphite  crucibles  were  made  from 
German  clay  and  water  to  which  is  added  sand  and 
Ceylon  graphite.  A  substitute  for  the  German  clay, 
however,  is  now  being  used  which  gives  exceedingly 
satisfactory  results.  The  mixture  of  clay,  water, 
sand,  and  graphite,  is  made  up  into  a  stiff  paste 
which  is  allowed  to  season''  by  keeping  it  in  a  damp 
place  for  several  days.  When  the  material  has  been 
properly  tempered  or  seasoned"  it  is  placed  in  a 
mold  upon  a  potter's  wheel  and  revolved.  A  movable 
mmmmf  profile  iron  spins  out  the  material  to  fill  the 


CARE  AND  STORAGE  OP  CRUCIBLES 


431 


mold,  at  the  same  time  acting  as  a  gauge  to  keep  tlie 
walls  of  the  crucible  at  the  desired  thickness  for  the 
purpose  in  hand. 

After  the  spinning  operation,  the  crucible  is  sea- 
soned for  another  24  hours  at  a  temperature  of  not 
more  than  80  degrees  Fahrenheit,  and  is  then 
smoothed  up  to  its  desired  form  ready  for  the  final 
seasoning.  This  final  seasoning  is  accomplished  by 
keeping  the  crucibles  at  a  temperature  sufficient  to 
drive  off  the  hygroscopic  moisture  for  a  period  of 
three  weeks.  They  are  then  placed  in  an  annealing 
oven  at  a  temperature  of  1500  degrees  Fahrenheit  and 
kept  there  for  three  days  to  remove  all  traces  of 
moisture.  This  process  is  termed  burning".  The 
finished  crucibles  are  then  protected  by  placing  them 
inside  clay  molds  to  prevent  oxidation  and  damage  of 
other  kinds.  Before  using  the  crucibles,  however, 
they  should  be  kept  for  a  considerable  time  in  a  warm 
place.  This  final  seasoning  tends  to  toughen  the 
crucible  and  give  them  greater  durability,  hence  they 
are  often  kept  for  some  time  after  being  made.  Cru- 
cible covers  are  generally  made  from  the  bottoms  of 
old  pots,  and  are  treated  in  the  same  way  as  the  cru- 
cibles themselves. 

The  scaling"  or  flaking,  which  is  sometimes  seen 
in  crucibles,  is  caused  by  improper  annealing  and 
seasoning.  The  material  of  which  they  are  made  is 
of  such  a  nature  that  it  absorbs  moisture  rapidly,  un- 
less prevented,  and  when  the  crucible  is  placed  in  the 
furnace  in  thi«  condition  the  moisture  is  converted 
into  steam,  causing  a  "flaking"  by  blowing  off  pieces 
.  of  th«  pot  entirely,  thus  rendering  it  unfit  for  use.  As 


432 


TOOLS  AND  PATTERNS 


pointed  out,  the  moisture  must  be  driven  off  by  a 
slow  process  of  annealing  and  tempering  in  order  to 
prevent  any  trouble  of  this  kind.  Crucibles  which 
have  been  thoroughly  dried  out  will  seldom  flake  or 
crack  when  heated,  and  it  is  therefore  of  supreme 
importance .  to  see  that  this  preparatory  work  is 
thoroughly  done. 

Storage  of  Crucibles. — The  prime  requisite  in 
the  storage  of  crucibles  is  that  they  be  kept  in  a 
warm  and  dry  place.  Where  pit  furnaces  are  used 
in  the  foundry,  an  excellent  place  for  storage  is  just 
back  of  the  battery  of  furnaces,  where  both  dryness 
and  warmth  will  be  assured. 

A  special  oven  can  be  arranged  which  utilizes  the 
waste  heat  from  the  furnaces,  and  by  using  dampers 
of  suitable  form  the  heat  can  be  regulated  to  make 
an  annealing  oven  of  it.  Whatever  arrangement  is 
made  for  crucible  storage  it  is  absolutely  essential 
to  provide  continuous  warmth,  and  not  have  an  in- 
terval during  which  the  crucibles  cool  off  and  ab- 
sorb moisture. 

Chora  in  tbe  Uae  of  Cmeiblis.— An  important  point 
in  connection  with  the  care  of  crucibles  is  to  prevent 
the  graphite  from  burning  off  the  outside  of  the  pots 
during  use.  An  oxidizing  atmosphere  will  do  this. 
Therefore  when  oil  and  gas  furnaces  are  used  for 
heating,  a  reducing  flame  must  be  kept  up.  A  badly 
burned  crucible  is  the  result  of  directing  an  oxidiz- 
ing flame  directly  upon  it;  such  a  crucible  is  soon 
ruined.  Better  results  will  be  obtained  by  using  a 
wider  flame  from  burners  adapted  to  high-pressure 
oil  and  low-pressure  air;  these  burners  are  more 


OABB  AW>  STOEAaE  OF  CRUCIBLES  433 


easily  controlled  and  not  so  severe  in  their  action  as 
burners  which  are  designed  for  low-pressure  oil  and 
high-pressure  air. 

In  mmkg  fuels,  those  which  have  a  high  content  of 
sulphur  form  sulphur  dioxide,  whiiek  is  very  injuri- 
ous to  crucibles.  Such  fuels,  therefore,  should  be 
avoided. 

Crucibles  will  last  much  longer  if  the  metal  is 
poured  as  soon  as  possible  after  the  proper  tem- 
perature has  been  reached  so  that  they  will  not  be 
subjected  to  the  burning  action  of  the  flame  any 
longer  than  is  needful.  The  life  of  crucibles  continu- 
ally kept  at  high  temperatures  is  comparatively 
short.  It  is  of  advantage,  therefore,  to  use  a  crucible 
first  in  melting  alloys  requiring  high  melting 
points,  then,  as  it  grows  older,  prolong  its  life  by 
melting  alloys  requiring  a  lower  melting  point.  It  is 
necessary,  of  course,  to  clean  out  any  alloy  of  one 
kind  thoroughly  before  using  the  crucible  for  another 
alloy,  in  order  to  prevent  hybrid  mixtures.  No  mat- 
ter what  melting  points  are  used  or  what  alloys 
are  melted,  care  must  be  taken  in  charging  the  pot 
not  to  crowd  it  full  of  scrap  or  heavy  ingots  of  metal, 
as  the  expansion  of  these  in  melting  is  sometimes  suf- 
ficient to  crack  or  otherwise  shorten  the  life  of  the 
vessel. 

Crucibles  will  have  longer  life  in  round  furnaces 
than  in  square  ones,  because  the  heating  is  more  uni- 
form in  the  former.  For  this  reason  tilting  furnaces 
are  easier  on  crucibles  than  pit  furnaces.  In  using  a 
pit  furnace  the  life  of  a  crucible  is  prolonged  by  plac- 
ing it  in  the  furnace  to  cool  gradually  with  the  fur- 


TOOLS  AND  PATTIBNS 


nace  rather  than  to  let  it  cool  in  other  atmosphere 
and  under  various  conditions. 

A  protective  paint  or  a  wash  made  of  pulverized 
carbonradiim  fire-sand  mixed  with  water  glass  or 
boric  acid,  has  a  resisting  effect  and  prolongs  th^  life 
of  a  crucible  to  some  extent.  A  coating  of  this  kind 
has  been  nsed  sucessfuUy  in  Europe  and  has  recently 
been  put  on  the  American  market 


INDEX. 


MMultwm  Aftiicial.  07 

Ai^taUe  FlztnM  for  ChMtag  9pw 

Gears,  248 
AilMteWs   Borlag   Tool    for  Tta^ 

Room  Work,  48 
— <!oaiiterbal»nce  for  a  Face-Plate 

rizturo,  175 
— ^for  Grinding  Bevel  Pinions,  250 
— ^ToniiBf  Tool  with  Roller-Back 

Rests,  59 

MMtmiang  Nn^  B»pnilag  Arbor  1m» 

188 

Air-Opwatod  Clraeks,  ISO 
Allowance,  Definition  of,  S49 
Alndirain  Casting,  Pragile,  Vertical 
Boring-Mill  Fixture  for,  228 

— TWn,  Fixture  for,  169 
Alnminnm,  Lubricants  for  CuttlBg,  293 
Ames  Dial  Test  Gauge,  380 
AagltauvOeiioratinf    Attachment  for 
Veriical  Turret  LotlM,  810 

— Croso-aiide,  208 

Angular  ICilling,  Fixture  for.  147 
Arbor,  Definition  of.  181 
— KxpsB^g,    as4   f!MO|»telo  for 

Vertical  Boring  Mill.  226 
— Expanding,  for  an  Adjusting  Nut, 
188 

— Saq^ding,    for"  an  AotaawMIt 

Usage,  186 
—Expanding,  for  a  Berel  Pinion,  180 

— ^Expanding,  for  a  Piston,  19i3 
— ^Expanding,  Split-Ring  Type,  184 
— ^for  Milling  Machine.  182 
— for  Plain  Lathe,  182 
— Knock-Off,  for  Tluroadod  CoUar% 
196 

— Special,  for  an  SooMtrle  Plaok- 

ing  Ring,  198 
— Threaded  and  Knock-OIT,  194 
ThrMM  Kaook-Off,  Ht  Tortioal 
Bffrfaff  ]fill.m 


— with  ExpaadlBg  Sboo,  188 
AxtUicial  AbrasiToa,  97 

Attarbment,  Angular  Generating,  for 
Vortieal  Tttrrot  lAtbe,  918 
—-for  Boring  an  latomal  SoiUtts, 
S17 

— -Badlvs-Forming,    for  Crowning 

Pulleys,  203 
— ^Radius-Generating,  for  an  Engiao 

Lathe,  301 
■  Badino-Gonerating,  for  a  Vertical 

Turret  Lathe,  214 
—Tapping,  for  Drill  Press,  188 
— Tttmiag  and  Boring,  for  Paeking 

Rings,  800 
— tarol    Lathe,    for  Generating 

Borel  Pinions,  211 
AltHMaHls  Bearlnga,  Testing  Align- 
ment of,  391 
— Cam  Shaft,  Testing  Throw  of, 

800 

—Crank  Shaft,  Vieolor  €Nmgo  for, 
399 

—Cylinders,    Sliding  Fixture  for 

Boring,  888 
—Flange,  Expanding  Arbor  for,  180 
—Fly-wheel,  Fixture  for,  224 
— Gas-Control  Plate,  Set-On  Jig  for, 

807 

—Hand  Lever,  Closod  Jlf  for,  274 

— Oil-Pump  Cover,  Drill  Jig  for,  260 
— Oil-Pump  Shaft,  Bushing  for,  270 
—Piston,  Kxponding  Pin  Cknck  for, 
192 

— ^Piston  Grinding  Fixtures,  243 
—Transmission-Case  Cover,  Set-On 

Jig  for,  800 
—Transmission- Case   CoTer,  Tran* 

nion  Jig  for,  284 
— Unltorwl  Jeiat,  Oriaiiat  ytxtaro 

Hr,  841,  940 


437 


BaU-StHlBf  Off  Intemtl  Grinding 

Fixture  for,  244 
Ball  Bearings,  Fluid  Gauge  for,  882 
Boariag  EBd-0a9»  Drill  3ig  for,  276 
Bearings,  Testing  Alignment  of,  391 
Becker  Continuous  Milling  Machine, 

Fixture  for,  188 
Boadi  Vises,  117 
^^■^^"g  Dies,  33 

Bovtf  Ooar,  Double.  Expanding  Arbor 

and  Faceplate  for,  226 
BOTOl-Oenerating   Attachment    for  a 

Turret  Lathe,  211 
Bovol  Piniinu,   Adjustable  GriniUng 
Fixture  for,  250 
—Expanding  Arbor  for,  189 
—Generating   Attachment  for,  on 
Turret  Lathe,  211 
Bevel  Ring  Gear,  Large,  Grinding  Fix- 
tore  for,  251  . 
— ^Vertical  Turret  Lathe  Attachment 
for.  216 

Bladoa,  Hacksaw,  Tooth  Spacing  of,  18 

Blanking  Dies,  29 

Blocks,  Johansson,  405 

Borax  Soivtion  as  a  Cutting  Lnbr^ 

cant,  293 

BOffng  and  Turning  Attachment,  Ec- 
centric, for  Packing  Rings,  809 

— an  Internal  Radius,  217 

Cylinders.  Sliding  Fixture  for,  233 
Boxing  Bars,  Flat-Cutter,  48 

— ^Types  of,  49 
Boring  Mill,  Vertical,  Fixtures  for,  220 

— Vertical,  Turning  Tools  for.  63 
Bodng  Tools,  46 

— ^Adjustable,  for  Tool-Room  W»k, 
48 

BOK  Totfl  for  Turret  Lathe  Work,  58 
Bracket,  Irregular,  Fixture  for,  178 
—Radius,  Drill  Jig  for,  280 
—Rod-Supporting,  Drill  Jig  for,  878 
— Slotted.  Fixtnre  for  End  MilUng, 
145 

— Small,  Open  Jig  for,  264 
Brass  Founding,  Crucibles  in,  429 
BroAches  for  Irregular  Holes,  95 

— for  Pour-Way  Koyways,  94 

—for  Round  Holes,  92 

— for  Square  Holes,  91 

— ^Varieties  of,  91 
BrffiHTbf''f  a  Round  Hole,  08 

— a  Square  Hole.  91 

— Preliminary  Treatment  in,  90 

— ^Purposes  of.  89 
Broachiag  Tools,  Varieties  of,  91 
BvUdlng  for  Storing  Patterns,  421, 
487 


iMShing,  Eccentric,  Drill  Jig  for,  278 

— ^for  an  Oil-Pump  Shaft,  270 
BttiiBOM  Aap«cts  of  Planning.  818 

Calipers,  Micrometer,  378 
Cams,  Electrical  Contact  Gauge  for 
401 

Cam  Shaft.  Testing  Throw  of,  396 
Castings,  Rough,  Self-Centering  Hx- 
tnre  for,  108 
— ^Thin  Aluminum,  Pixturo  for,  109 
C-Clamps,  116 

Ooitexing  Fiadnro  for  a  Rough  Casting, 

168 

Chatter  in  Planer  Tools,  22 
Chips,  Removal  of,  by  Stream  of  Lubri- 
cant, 295 
Chisels,  Cold,  Forms  of,  12,  14 
Chnddng  Boaaion,  Fluted.  4& 

— ^Rose,  42 
Chucks,  Air-Operated.  130 

— Collet,  124 

—Drill,  and  Sockets,  180 

— Four-Jawed  Independent,  188 

— Geared  Scroll,  129 

—Magic,  121 

— ^Magnetic,  240 

— Step.  126 

— ^Two- Jawed,  127 
Clrcnlar  Cover  Patterns,  410 

— ^Forming  Tools.  71 
Clamp,  Toolmakers,  115 
Classification  of  Files,  8 

— of  Hand  and  Forged  Tools,  7 
day  Oraeiblos,  Manufacture  of;  489 
Closed  Jigs,  270 

— ^for  a  Bearing  Cap,  276 
—for  a   Rod-Supporting  Braekot. 
872 

— ^for  an  Oil-Pump  Bushing,  270 
— ^for  Automobile  Hand  Lovor.  974 
OolA  Chisols,  12 
—Angles  on,  18 
— Forms  of,  14 
CoMMn,  Threaded,   Knock-Off  Arbor 

for,  196 
CoUets  and  Cl^ucks.  125 
Oonhiaatlon  Phltwn  for  PnUeys  or 

Gears,  424 
Compositton  of  Cutting  Lubricants,  291 
Ooaiponnd  IHoi,  31 
Concentricity  Indicating  Gauge,  404 
Conditions  of  Manufacture,  2 
Oomaectlng  Bod,  Automobile,  Simple 
Straddle-Mining    Vlsctiiro  for, 
141 

— ^Automobile,     Double  Straddl«- 
Milling  FtzHirf  for,  143 


438 


INDEX 


INDJBX 


4ad 


391 


— Faee-PIate  Fixture  for,  172 
OoBUaaous  Milling  Machines,  1S4 

— ^Becker,  Fixture  for,  158 
Otaltuoas  Bfilliiiff  Hxtanrt  for  Avio- 
mobile  Cylinders,  156 

— BImple  Type  of,  155 
Owttu^  Unh-Pia  €Nnig«t  for,  S89 
Cooling  by  Lubrication  in  Cattll^ 
C«P«»  DefiaiUon  of.  409 
OoTO  Diffii^  38 

— Example  of,  39 
CJores  and  Core  B<aea,  411 

— ^Baked.  413 
Cost  Estimation,  337 
CooBtwbalance,    Adjustable,  for 

Face-Plate  Fixture,  175 
dMMtarbttlaiicod  Flzturo  im  m 

necting  Rod*  178 
Connterbores,  39 

— Types  of,  40 
Crank  Sbaft,  Feeler  Gaugo  f»,  999 
Cross-Slide   for   Generating  AngBter 

Cut  OB  Riag  Gears,  808 
Crown,  Pulley,  Forming  the,  208 
Cradbles,  Care  in  tbb  Use  of,  488 

— day,  Munfaetoro  of,  429 

— Graphite,  Manufaeturo  of,  4811 

— ^Pouring  the,  433 

— Storage  of,  432 
Curling  Dies,  33 

Curved  Surfaces,  GenoKstiag;  800 
Outters,  Angular,  79 

— ^Milling,  75 

— Slotting,  78 
Catting  Action  of  Lathe  Toola,  28 

—of  Planor  Tboli,  81 
Catting  Dies,  30 

Catting  Fiztnres,  Adaptability  of,  288 
OtMtag  lAbrlcant,  EfiFect  of,  on  Speeds 

and  Feeds,  309 
Cntting-Off  Tools,  64 
Catting  Speed,  Definition  of,  301 
— ^Ptmmila  for  Dotoradaiiig,  808 
— Table  of,  307 
Catting  Tools,  Lubrication  of,  289 
Cylinders,     Automobile,  Continaooa 
Milling  Fixtaro  for,  156 
-External,  Ring  Gauges  for,  368 
— Sliding  Fixtare  for  Boring,  233 
Ofibn§fKt  CMB4te8t  108 
OfUndrical  Grinding,  External,  BoM* 
ing  Work  for.  239 
--Methoda,  104 
QyllBdrical  BriM^  Hnf  Gnngos 
357 


Depth  Gauge,  Flush-Pin,  386 
Designer,  Tool,  Work  of  the,  315 
MnOa  of  Manafactnring,  1 
Dial  Indicator,  Ames,  379 
Di«4,  Bending,  33 

— ^Blanking,  29 

— Compound,  81 

— Curling,  33 

— Catting,  30 

^Iknre-Tailed    Drop  Vovft, 

ample  of,  27 
— Drawing,  33 

Tollow,  Ezamplo  of,  80,  88 
— ^Forming,  32 
— Gang,  Example  of,  33 
— Progressive,  Example  88 
— 'SliAping,  30 
— Snthpreas,  34 
— JIMeai,  81. 
— Taps  and  Holders,  136 
— ^Trimming,  Example  of,  on  Roagh 

Forging,  30 
Wmmtlmm,  Uniting,  on  Brswints, 

856 

IMllortlOB  in  Fragile  Work,  Fixtare  to 
Prevent,  228 
— in  Patterns,  423 
DoaUa  Fhish-Pin  Depth  Gange,  390 
—Indexing   Fixture   for  Straddle 

Milling,  149 
— SpUne-MiUing  Fixtare,  161 
— Straddle-Milling   Fixtare   for  a 
Connecting  Rod,  143 
DoTO-Talled  Drop-Forge  Dies,  Exaaq»le 

of,  27 
llmA  Definition  of,  409 
Drawing  Dies,  33 

Drawings,  Marking  Limits  on,  356 

Drill  Chucks  and  Sockets,  120 

IMn  JXg;  Closed,  for  a  Bearing  (^p, 

276 

— for  a  Crooked  Lever,  283 
— for  an  Beeentrie  Boshing,  278 
— ^for  an  Oil-Pamp  Cover,  260 
— ^for  a  Radius  Bracket,  280 
— ^for  a  Rod-Supporting  Bracket,  272 
— ^Functions  of,  253 
Dim  Jifi,  Open,  253 
—for  a  Lever,  261 
—for  a  Le¥ar  with  Stnd  Loeater. 
263 

—Plate,  with  Supplementary  Sup- 
porting Ring,  258 
Drill  ¥x9n,  Tapptng  Atlnehment  for. 
188 

Drma,  Oore,  88 
— Fim  Twitl.  88 


— Shapes  and  FOCTM,  86 

— Spotting,  36 

—Twist,  37 

— ^Types  of,  36 
Mn  Fit,  Definition  of,  347 

— ^Table  of  Tolerances  for,  854 
Dfot-Forge   Dies,    Dove-Tailed,  Ba- 
ample  of,  27  .  «. 

 ^th  Space  for  Reeriving  wm,  89 

mo9  ForgSttg*  Method  of  FroTtdinf 
Holes  for,  31 

— ^Principles  of,  26 

Bccentric  Fixtare  for  a  Blag  Pot,  177 

Swinging,  178 
BeeenMc  Packing  Ring,  Special  ArM 
for,  198 

— ^Tnming  Attachment  for  Packing 

Rings,  209 
—Work.  Simple  Fixtare  for  M«r 
chining,  231 
Electrical  Contact  Gauge  for  Cams,  401 
Snd-C»p,  Bearing,  Drill  Jig  for,  276 
Bad  Milling  a  Slotted  Bracket,  Fix- 
ture for,  145  e 
BafiBe  LaSlie,  Simple  Radias-Genemt)* 
ing  Attachment  for,  201 
— Simple  Recessing  Tool  for,  51 
f^prfywut,  Standard,  for  Tool  Crib. 
120 

— Standard  Tool,  for  the  Shop,  110 

Bstiinatea,  Making  the,  380 
—on  Labor  Expense,  340 
—on  Overhead  Expense,  343 

BitlBUkting  Costs,  337 

Bipnnding  Arhor  and  Faceplate  lof 
Vertical  Boring  Mill,  226 
— ^for  an  Adjusting  Nat,  188 
— fwr  an  Automobile  Flange,  186 
— for  an  Automobile  Piston,  198 
— for  a  Bevel  Pinion,  189 
— Split-Ring  Type,  184 

•mrft/pMng  Fm  Cnintik  for  a  Piston, 
198 

Tg*r«W^*t  Type  of  Arbor,  188 

ISfffi^i  OfUndrical  Grindiaik  Hold- 
ing Work  for,  239 
— ^Form  Grinding,  108 

— Gauges,  364 

— ^Tapers.  Grinding  Methods  for,  108 

ftee-Flate,  Expanding  Arbor  and,  fw 

Vertical  Boring  Mill,  226 
Fkee-Vlste  Fiztan»  Ckninterbalaneed. 
for  a  Connecting  Rod,  172 

 ^for  an  Irregular  Bracket,  172 

— ^for  a  Ring  Pot.  177 

—for  CaltiBf  Fteking  Bisft,  180 


— for  Hub  Flange,  167 
—for  Qaantitr  Frodnetion.  185 
—for  Thin  Aluminum  Castings,  169 
— Self -Centering,  for  Rough  Casting, 
168 

 Standard,  for  Engine  Latbe,  165 

— Swinging  Eccentric,  178 

 ^^th  Adjustable  Coanterbalanee, 

—with  Safeguarding  Devices,  172 
I  Influencing  Selection  of  Min- 
ing Machines,  73 
and  Speeds,  Effect  of  Catting 
Lubricant  on,  309 
—Relation  of,  to  Catting  Speeds. 
304 

Feeler  Oaage  for  a  Crank  Shaft,  399 
Female  Master  Gauge  for  Testing  Male 

Taper  Gauges,  361 
— ^Taper  Limit  Gauge,  372 
— ^Thread  Gauge,  374 
Finale  Taper  Gang e^  Reference  itsBge 

for,  373 
Files,  Classes  of,  8 

— ^Forma  of,  9 
Pin,  Removal  of,  in  Drop  Forging,  28 
Fire  Protection  in  Pattern  Storage, 
428 

Fishtail  Catters,  78 
Pita,  Variety  of,  in  Manufacture,  3« 
Pi3Ctare»  Continaoaa  Mining,  for  Cfyi- 
inders,  156 
 Counterbalanced,  for  a  Connecting 

Rod,  172 

—Catting,    AdaptabiHty    of,  for 

Grinding.  238 
— Doable-Indexing,     for  Straddle 

MOUng,  149 
— Beeentrie,  for  a  Ring  Pot,  177 
 Faee-Plate,  for  Quantity  Prodmc- 

tlon.  165 
— for  Angular  Milling,  147 
— ^for  an  Irregular  Bracket,  172 
—for  a  Fragile  Aluminum  Casting, 

Vertical  Boring-Mill.  228 
 ^for    Becker   Continuous  Milling 

Machine,  158 
 for   Continuous   MllUng,  Simple 

Type  of,  155 
— for  Doable  Spline  MlUlng,  161 
.^or  End  MllUng  •  Slotled  Bmeket, 

145 

— ^for  Form  Milling,  148 

— ^for  Gang  MllUng,  145 

 ^for  Holding  Antomobile  Fly- 
wheel, 284 

—for  Plain  snd  8tra441e  MllUng. 
189 


440 


INDEX 


-^^§n  Spttm  Miniiif ,  160 
— ^for  Thin  Aluminum  CmUm** 
— lor  Thin  Work.  221 
— iin>  yertieal  Botteg  KUk,  StO 
•-^rinding,   for  UaHmHil  Joist, 
241.  246 

^late  Hilling,  for  Qaoatltj  FM- 

dvetion,  150 
— Kstnre  and  Variety  of,  139 
— ^Simple,  for  Machining  an  Eccen- 

trie.  2S1 

^Sliding,   for  Boriag  *  FHir  of 

Cylinders.  233 
— -8poci^,  with  Tfcponfl  Ii»> 

cater,  224 
— Straddle-Milling,  for  a  Obaaoet- 

tittg  Rod,  141 
— Swinging  Eccentric,  178 
— ^with  Adjiutable  Coanterbalanee, 

ITS 

— with  Safeguarding  Devices,  172 
Tlangt,  Automobile.  Bnp^aiHng  Arbor 

for.  186 
Flask.  Molding,  409 
Flat-Cnttor  Boring  Bars,  48 
Flat  Twist  Drills.  38 
Flood  Lnbricatioii.  for  Cnttias.  MMI 
Flnld  Gauge,  Prestwich,  880 
Flush-Fin  Gauges.  385 

— I>ottb]*,  800 

— for  Contours,  380 

— for  Tapers,  388 

—with  DM  iBdicfttor.  Stf 
Fluted  Beamers.  Plain,  42 
Fljwhoel,  Automobile,  Fixtnro  for,  224 
Vmw  VN^  DeAnltion  of,  840 

— Table  of  Tolerances  for,  854 
Ford  Motor  Flaat  an  Ezauplo  of  Plna- 

nhig.  818 
fbrgod  Tools.  1 

— Varieties  of,  19 
Vorging,  Drop,  Principles  of.  !• 
Follow  Dies.  Example  of,  32 
Formed  Milling  Cutters,  81 
Form  Grinding,  External,  106 
W&mtng  and  OrooTtef  AttadOMBl  for 

Pistons,  206 
Forming    Attachment,    Radius,  for 

Crowning  P)dlev«,  SOS 
Forming  Dim,  32 
Forming  TooU^  68 

— Ofarenlsr.  Tl 

— ^for  Turret  Lathe  W4ffk,  ftf 

— ^Rectangular,  68 
Wmm  ■nUng;  nxtnr*  for.  148 
Vtnnia   for    DetsnriBlaf  Oiittiag 

Speeds,  302 
VMT-Jawtd  Independent  Chuck,  181 


Vfif^Wagr  K«]rw»F  BroMhes,  04 
Tnm  ITmi  SketohM  In  iMglmg  Out 
WoriE,  880 


Gang  Dios,  EzMnple  of,  88 
Ooag  MiniBg;  FIstnro  for,  145 
OM-Control  Plate,  Set-on       fttr.  107 
OMgoSf  Ames  Dial  Test.  380 

— OoMtntrieity  Iniientiag.  404 

— Xloetrical  Contact,  401 

— Kxtemal,  364 

— ^Feeler,  for  a  Crank  Shaft,  399 
"  Flwnale  Thread,  874 

— Plush-Pin,  385 

—Indicating,  for  a  Cam  Shaft.  806 
— Indicator,  for  Toatiag  AUgaaMat, 

391 

— ^Internal  Limit,  857 
^latmial  TupiKr,  800 

— Johansson,  405 

— Master,  for  Female  Tapor  Gangea, 
878 

«^tec«r,  tm  Mala  Tt^m  Oaagai, 
801 

Micrometer,  878 

— Plug,  858 

—Prestwich  Fluid,  880 

«^ProiUe  and  Indicating,  370 

— ^Proila  Inspection,  401 
.  -—-Receiver,  870 

— Ring,  868 

-^a«|>.  M6 

— Taper  Ring,  171 

— ^Templet.  867 

-—Thraad,  Malo.  801 
Oaaging,  Terminology  of,  340 
Oaarod  Scroll  Chucks,  129 
Oaicii;  Bovd  Ring,  CMnding  nztnra 
for.  251 

— ^Bevel  lUng.  Vertical  Turret  Latha 

AttaeHMiMit  for,  216 
—Combination  Patterns  for,  424 
—Double  Bevel,  Expanding  Arbor 

and  Faceplate  for,  226 
•"-^Uag,  Cross- Slide  for  Ctoaaratiag 

Angular  Cut  on,  208 
—Spur,   Adaptable   Grinding  Fix* 
ture  for,  248 
Ooar  Molding  Machine,  425 
Ooar-Tooth  Milling  Cutters,  81 
QcOaMBg  Angular  Cut  on  Ring  Gears. 
Cross-SUdo  for,  208 
— Curved  Surfaces,  200 
Oonerating  Attachment,  Angular,  for 

Vertical  Turret  Lathe.  110 
OO  and  Not  Go  Gauges,  358 
ttOiM-Heck  Threading  Tools.  67 


IMPIX 


Oiapliiie  OxwdUev,  Ctmmmm  ef» 

480 

— ^Manufacture  of,  430 
Offniifig^  Bxtemal  Cyllttdrl«»l.  Hold- 
ing Work  for,  239 
— ^External  Forms,  106 
—External  Tapers.  106 
—Interior  of  Amtomeblla  Cf  ii»d«a. 

Spur  Gears,  248 
—Adjustable,  for  Bevel  Pinions,  250 
—for  AutomobUe  Pieton,  248 
qrtB#itg  nztnza  for  a  Large  Bevei 

Ring  Gear,  251 
—for  Universal  Joint,  241,  240 
—Internal,  fer  a  Ball-B«tfliit  CSaga 

244 

— ^Internal,  107 

— Surface.  100 
Grinding  Tool*.  24 
Orindlng-WheelB,  Shapes  of,  99 
OtoavlBg  Attachment  for  Pistons,  200 

MMtoaws,  10       „  .  , 

Bkad  and  Forged  Tools,  1 

Bind  Lever,  Automobile,  Jig  «»,  274 

Biad  Vises,  114       .    „  , 

Bead.  Multiple  Turning-Tool,  62 

Bob  MilUng  Cutter,  88 

ig^tMmirm  for  Tapa  and  Diee.  180 

— for  Tools,  25 
BttMiBf  Work,  Necessity  for.  l»  »"i- 

'tng,  140  ^  - 

Belii,  Cf^mmeal  TUg  Ganges  for, 

— in^p  ftirghige.  Method  of  Fm- 

—Round,  Broaching  Cut  for,  8» 
-—gonare,  Broaching  Cut  for,  91 
—Standard,  Table  of  Tolerancea  for, 
352 

mmmr  Mins,  55 

— Types  of,  56  -  , 

Boiiiontal  twwl 

Lubrication  of.  for  Drilling.  296 
M  Flange,  F»ee-Plate  Fixture  for. 

167 

independent  Chuck,  Pour-Jawed,  132 
Index  Milling  a  Pair  of  Levers,  149 
■^-SHxtiife  for  ^ttihtlfsr  Pw>«tt«tlon. 
150 

XBdaz  of  Machine  Tools,  319 
 of  Pattefjil.  415 


Indicating  Gauge  for  a  Cam  Shaft,  396 

— ^for  Concentric  Surfaces, 
jmUfff^  Oaage  for  Teatiag  Align- 

aaent.  391 
SaUeiMen,  Dial,  379 
maected-Blada  Milling  Ctttler.  85 

— Reamers.  43 
InspectKm  Gauge,  Profile,  402 
Instnuaeota  of  Preetsloa.  877 
Interchangeable  Manufacture,  3 

— ^Degree  of  Accuracy  in.  346 
Interchangeable  Work,  Limito  for.  851 
Interlocking  Milling  Cutters,  86 
Intamal  Grinding  Fixture  for  a  Bali- 
Bearing  Cage,  244 
mitail  Grinding  Methoda,  107 
— ^Limit  Gauges,  357 
—Radius  Boring  Attachment,  117 
— ^Taper  Gauges,  359 
magnlar  Bratikal»  Face-Plate  Fixture 
for,  172 

nge.  Closed,  270 
^-for  Automobile  Hand  Lever,  274 
—for  an  Oil-Puinp  Bushing,  270 
-for  a  Rod  »mppmUa€  Bracket. 
272 

Jig,  doeed  Drm,  for  a  Beaviag  Gep, 
276 

-*-for  a  Crooked  Lever,  283 

 ^for  an  Eccentric  BusMng,  178 

 for  a  Radius  Bracket,  280 

Jig  Drill,  for  an  Oil-Pump  Cover,  260 

—^Functions  of,  258 
Jig,  Open,  for  i  Lever,  261 

 for  a  Lever  with  Stud  Locator,  263 

— for  a  Small  Bracket,  264 
Jlgt,  nnte,  with  Svpplementary  8«r 

porting  Ring,  258 
71gi  Set-On,  ioT  a  Gas-Control  Plate, 
167 

»for  a  Traaemlailon-CaBe  Cover, 
266 

Jigs,  Simpio  Floie,  for  DriRlng.  156 
Jlg^  Trunnion,  for   a  Tmaavieaion- 

Case  Cover,  284 
Johansson  Gauges,  405 

Xno^-Off  Arboct  for  Threaded  Col- 
lars, 106 
—Threaded,  194 

 Threaded,    for   Vertieal  Bonng 

MiU,  235 
BiVVlV  BvMdMt,  01 

I«rd  Oil  as  a  Cutting  Lubricant,  101 
Lalhn^  Plain.  Arbor  fi».  181 
Xisfha  fooUi  Gnttittg  Aetioa  of,  18 


442 


timating  Costs,  340 
Lajrinc  Out  Work  in  the  Machins 

Shop,  817  • 
SifiNt  of  Jigs.  FixtvM,  TMdi,  maM 
Oaaeres,  322 
~of  Maehine-Tool  Equipment,  319 
— of  Operations,  318 
— of  Operation  I^Mta,  323 
— Sheets,  330 
Imd  of  Thread,  Definition  of.  889 
£«for,  Crooked,  Drill  Jig  Utt,  988 
— ^Hand.  Jig  for.  274 
--Mis  MflHiig  •  P»ir  of.  140 
— Open  Jig  for,  261 
— Open  Jig  for,  with  Stud  Locator, 
M8 

Limit,  Definition  of,  350 
Limit  Gangea,  Internal,  357 

— ^Taper,  for  latonal  Tapered  Holo^ 
360 

Halting  Dimensions  on  Drawings,  856 
Itetts  for  Interchangeable  Work,  351 
iMBtlng  WSHt;  y-Blodi  Friaeipte  of. 

170 

Lubricants,  Composition  of,  for  Cut- 
ting Ahuninum,  298 
— CompoaMoiB  of.  Inr  Onttfag  Stool. 
893 

•—Sffoot  tit  «i  CHrttfBff  Spooia  wmA 

Wmis,  309 

 StWMMa  of.  for  Removing  Chipa. 

995 

IflfMcatlng  a  Horizontal  Ttamt  Lath*. 
IntemaUj,  295 
— •  muTOt  Latho  through  the  Spin- 

die.  296 
— a  Vertical  Turret  Lathe,  299 
Lnhrleatimi,  Flood,  for  Cutting,  298 
—Off  Cuttiag  1Mb,  999 

Machine  Equipment.  119 

— ^for  Molding  Geara,  425 
MiAine-Tool  EquipMU,  919 

— ^Index,  319 

~Sooor4  Card.  991 
Machine  Vises,  134 
lAkgic  Ohuek,  121 
Mif  OHff  OfeMfca^  940 

— Description  of,  100 
Male  Master  Gauge  for  Testing  Fo- 
male  Taper  Gauges,  878 

— ^Taper  Qfl«9«»  B«tarOM«  QMfa  fM; 
361 

— ^Thread  Gauge,  362 
Mandrel,  Definition  of,  181 
Manufacturing  Details,  1 
Manofacturing  Vises,  134 


jfaitiiig  the  Pattern,  490 
liMlor  Gfttigw  for  Malo  Tmpw  &m9m, 
361 

— for  Female  Taper  Chragoa,  878 

Metal  Patterns,  Advantages  of,  424 
Micrometer  Ganges,  Constmction  Foft- 

twrea  of,  878 
Uniiiif  Wima,  Angiriw.  79 

— Formed,  81 

— Gear-Tooth,  81 

— ^ob,  83 

— Inserted-Blade,  85 

— Interlocking,  86 

— Plain,  86 

— Shell-End.  77 

—Spiral,  75 

— Straddle,  85 

— Straight-Fluted,  75 
miling.  Gang,  Fixture  for.  145 

— Prooeases,  79 
XUling  Machine,  Aitor  for,  182 

— ^Factora  Influencing  SoloctioB  of; 
78 

Mills,  Hollow,  55 

MlBnal  Oil  aa  a  Catting  Labrieaat. 
391 

MBlilBg  a  Flanged  and  Bi¥bod  Pat- 
tern, 418 

— Clay  Crucibles,  429 

— Method,  400 
Molding  Bfachlne  for  Goan.  d9S 
Molding  Sand.  411 
llona  Tkpw,  180 

MOtlple-Splndle    Drilling  MacfMliaa, 

DriU  Jigs  for,  253 
Ifalll^YaniBg  Tool  Head,  09 

Natural  AbzaaiTea,  07 

Vawall  BBftnoozliic   Co..   TaUo  of 

Limits,  355 
Vowel,  Definition  of,  409 
Vut,  Adjusting,  Expanding  Arbor  fw. 

188 

on  aa  a  Cutting  Lubricant,  291 
OlliBff    ARaafUMmt.    Intwaal,  for 

Drilling  on  HoriaoBtal  Torrot 

Lathe,  296 
Oa-Pamp  Cover,  Drill  Jig  for.  900 

— Shaft,  Bushing  for,  970 
Opon  DzlU  Jigs.  253 
(^aa  Jig  for  a  Lover,  861 
^or  a  Levar  witk  Stai  Laoator. 

263 

—lor  a  Small  Bracket,  264 
Opt  Side  Turning  Toola,  60 
(^ration  Layout,  318 
Operation  Sheets.  Layout  of,  328 


INDEX 


443 


Overhead  Expense,  Estimating  the.  848 
Orerhead  Turning  Tools,  60 

Packing  Bing,  Eccentric,  Special  Arbor 
for,  198 

— ^E6centric  Turning  and  Boring  At- 
tachment for,  209 
— ^Fixtures  for  Cutting,  166 
PaddBg  Ring  Po^  Swinging  Becentric 

Fixture  for,  179 
Parallels,  112 

Pattern  Makers'  Tools,  419 
Pattern  Records,  Importance  of,  421 

— Cards,  425 
Patterns,  Circular  Cover,  416 

—Combination,    for    Pulleya  and 

Gears,  424 
— Composition  of,  407 
—Construction  of,  408 
—Finish  of.  422 
—Fire  Protection  of.  428 

 ^Flanged  and  Ribbed,  418 

— ^Index,  425 
— Location  of,  427 
— ^Marking  System  for,  426 
— Metal,  Advantages  of,  424 
— ^Method  of  Molding.  410 
— One-Piece,  409 
— Quality  of,  422 
— ^Ring  and  Spider,  424 
— Sectional.  «98 
— Skeleton,  419 
—Sweep,  410 
— Three-Part,  417 
— ^Two-part,  414 
— ^Warpage  of,  428 
Pallani  Stoxaga  Building,  421,  497 
— ^Fire  Prevention  in.  428 
— ^Method,  427 
Pivmaaeat  Tools,  Definition  of,  5 
Parishable  Tools,  Definition  of,  5 
Plaoo-Work  Prices,  Determination  of, 
885 

Pfloltd  Turning  Tool  tor  Rapid  Pro- 
duction, 61 

Pla  Chock,  Expanding,  for  a  Piston, 
199 

MiaiB%  Bavel,  Adjustable  Grinding 
Fixture  for,  250 
— ^Expanding  Arbor  for,  180 
—Turret  Lathe  Attachment  for  Gen- 
erating, 211 
Pipe  Vises,  117  • 
plalOB,   Automobile,   Expanding  Put 
Chuck  for,  192 
— Cast-Iron,  Time-Study  Sheet  on. 
333 


— Caat-Iron,    Tool    and  Operation 

Sheet  for,  824 
— ^Forming   and   Grooving  Attach- 
ment for,  206 

 Generating  Curved  Bnda  of,  901 

— Grinding  Fixture,  243 
— ^Prestwich  Gauge  for,  388 

 ^Tool  Layout  Sheets  for,  328 

Plata  Chucking  Reamers,  42 
— Fluted  Reamers,  42 
— ^Milling  Cutter,  86 
Plata  MUCttag,  Fixtures  for,  189 
plaaing  Tools,  87 
— Chatter  in,  22 
— Cutting  Action  of,  21 
jpiannlng,  Business  Aspects  of,  313 
Plata  Jig.  Simple,  for  Drilling,  256 

 ^irlth  Supplementary  Supporting 

Ring,  258 
Plug  Gauges  for  Cylindrical  Holes,  857 
Plag  Locator,  Tapered,  for  Holding  a 

Flywheel.  224 
Poppet  Valve,  Receiver  Gauge  for,  371 
Pooling  the  Crucible,  433 
pfoelia  Measuring.  877 
Prestwich  Fluid  Gauge,  380 
PxlBCiples  of  Drop  Forging,  26 

-^f  V-Bloek  in  Locating  Work,  170 
Praflla  and  Indicating  Gauges,  876 

— ^Inspection  Gauge.  402 
PMgxosai^ft  IMas,  Example  of,  82 
ptiBoya,  Combination  Patterns  for,  424 
— Faeing  on  Vertical  Turret  Latho, 
814 

— ^Forming  thO  Crown  of.  208 
Plih  Fit,  Definition  of,  347 

 Table  of  Tolerancea  ftor,  854 

Ponp  Oofir,  on.  Drill  Jig  for.  900 

llultly  of  Patterns,  438 

Badiaa  Boring.  Internal,  Attachment. 
917 

Badins  Bracket,  Drill  Jig  for,  280 
Badtaa-Porming  Attachment  for  Crown- 
ing Pulleys,  203 
tttMoB-Qaa/vnlting  Attachment  for  a 
Vertical  Turret  Lathe,  214 
— ^Attachment,  Simple,  for  an  Ba- 
gine  Lathe,  901 
Baamers,  41 

— ^Inaerted-Blade,  43 
—Plain  Chucking,  42 
— TltAn  Fluted.  42 
— ^Rose  Chucking,  42 
— Tap^.  44 


INDEX 


BMMSing  Tools,  50 

— for  a  Large  Steel  Casing,  54 

— 4tor  Tmnt  WtoAt,  tS 

— on  an  Enjcine  Lathe,  51 
Bacord  Cards  for  Patterns,  4SS 

—of  MaeMM  Voals.  tSl 
Records,  Pattern,  Importance  af,  itl 
Bftangator  Forming  Tools, 

— MagMlie  OmOm,  240 
Caference  QsagM^  Vlniili|»  MS 

—Male  378 
BMti^    Roller-Back,    for  Adjustable 

Turning  Tool,  59 
BliS  and  Spider  Patterns,  424 
■tug  CNMigas  for  Cylindrical  Work,  368 

— far  Tq^rs.  372 
Mai  Gear,  B«vi|»  CMa4iaf  VIztaM 
for,  251 

— Tarlieal  Tmmii   Latka  Attadi* 

ment  for,  216 
Mng  €toan,  Cross-Slide  for  Oanerating 

Angvlar  Cist  on,  908 
Ring  Pot,  Pace-Plate  Fixture  for,  177 
— ^Packing,  Swinging  Eccentric  Fix- 

tw  fvt,  1T9 
m§A  Drill,  Vertical  B^rimg  MM  fla< 

ture  for,  235 
M-SBpp«rliBf  BncMk  IMll  Jig  far, 

272 

BaOar-Back  Bests  for  Adjwialil*  Tam- 
ing Tool,  59 
Rose  Chucking  Reamers,  42 
Rotary  Magnetic  Chucks,  240 
Round  Holes,  Broaching  Cut  for,  92 
BOTinlng  Fit,  Definition  of.  847 
— Table  of  Talaraaaii  faa;  M 


Safatj  Davlcas  on  a  Face-Plate  Fiz- 
tare,  172 

816 
SanpM%  15 

— ^Types  of,  18  * 

— ^Use  of.  16 
8a«M»  M easnring  tha  Laad  af,  ttt 

— Templet  Gauge  for,  368 
Scroll  Chucks,  Geared,  129 
Saexvl  of  Cost  Estimation,  340 
iMlllMl  FlattanM,  4SS 
Mf-Cmterlng  Fixtnra  itr  •  Bobi^ 

Casting,  168 
Sat-On  Jig  for  a  Gas- Control  Plate, 
S67 

266 

asflit  Dial  Ttat  Ganft  far  T— paattiig. 


— Limits  for  Length  of,  355 

— Tapered,  Flush-Pin  Gauge  for,  388 

ShapiBg  IMaa,  80 

Shell-End  Milling  Cutters.  77 

Shells,  Gauge  for  Indicating  Concen- 
tricity of,  404 

Shop  EqnlxnBent,  Standari,  110 

SIda  MilUng  Cutter,  85 

SkilaloB  FrtlUM,  419 

Sketches,  FreO'Hiuid,  for  Work.  330 

aUdlnf  Flxtnxa  for  Boring  a  Pair  of 
Cylinders,  888 

ftolltac  thMma,  78 

Snap  Gauge,  for  Cylindrical  Work,  84i 
— ^for  General  Dimensions,  366 

Soefcata;  Drin,  120 

Stiawatar  as  a  Cutting  Lubricant,  292 
gpiada  and  Faada,  Definition  of,  801 
-4ffaet  of  Ototttag  LsMamI*  «b. 

309 

— General  Rules  for,  310 
— -InportaBca  of  Prapar,  807 

Smia,  Cutting,  Forarala  Inr  Boter* 
mining,  302 
—batting.  Table  of,  807 
— Relation  of,  to  Feeds,  304 

Spidar  and  Ring  Pattema,  484 

SpiZBl  Miniiig  Cottars,  75 

Spline-MllliBf  nztwaa*  160 

Split-Ring  Expanding  Arbor,  184 
—Expanding  Arbor  for  mi  A4ttMt- 
ing  Nut,  188 

Spotting  Drill,  36 

Spar  (Jaars,  Adaptable  Grinding  Fix- 
ture for,  248 
Square  Hole,  Broaching  Cut  for,  91 
Standard  Face  Plate  for  Engine  Lathe, 
165 

— Tool  Equipment  for  the  Shop,  110 
Steal,  Lubricants  for  Cutting,  208 
n&9  Otaeka»  186 
aiatafa  of  Crucibles,  482 

— of  Patterns,  427 
Straight-Edges,  112 
Straight-Fluted  Milling  Cutters,  71 
Straddle  Milling  Cutter,  85 
atraidle  Milling,  Double-Indexing  Fix- 
ture for,  149 
MaAdla-Milling  Fixtoxa  for  %  Oo» 
necting  Rod.  141 
— ^Working  ftroa  a  flaltlMi  tafiM, 
148 

Stud  Locator  for  Open  Jig,  263 
Sub-Press  Dies,  34 
Surface  Grinding  MaOutda.  100,  lOS 
Surface  Plates,  111 

Bm*m  fiHtwii-Aio 

Maflit  Sc««atrie  nxtar^  178 


INDEX 


443 


Tandem  Dies,  31 

Sapazad  Hoitb  Bolding  Wurk  If  tk^a, 

225 

Tapered  Plug  Locator  for  Holding  a 

Flywheel  224 
Tapar  Gauge,  Female,  Reference  Gaogo 

for,  373 
— ^Internal,  859 

— Male,  Reference  Gauge  for,  861 
Tapar  Pins,  Receiver  Gauge  for,  370 
Vapw  Baamaca,  44 
Taper  Ring  Gauge,  372 
Tapars,  Designation  of,  120 
Flush-PIn  Ganges  for,  888 
— Grinding  External,  106 
Tapping  Attachment  for  Drill  Press. 
128 

Taps,  Dies,  and  Holdars,  180 
Tao-Slot  Cutters,  78 
Templet  Ganges,  367 
— for  a  Screw,  368 
TUB  W6rk,  Fixture  foiv  OH  Taitiial 

Boring  Mills,  221 
Thiaad-Ohaabig  Tools,  66 
Threaded  and  Knock-Off  Arbors,  194 
Threaded  Collars,  Knock-Off  Arbor  for 

196 

Tbttadad  Enock-OIT  Arbor  for  Yartf- 

eal  Boring  Mill,  235 
Tluraad  Ganga,  Inspaetioa  of,  by  Viaid 
Gauges,  384 

— ^Female,  374 

—Male,  869  . 
Tlfaadlng  Tools,  65 

— Goose-Neck,  67 
Tllna-Part  Fattomi,  417 
Time  Factor  in  Cost  Esttmataa,  tST 
Time-Study  Sheets.  332 
Tolerance,  Definition  of,  349 

— ^for  Push.  Drive,  and  Fwea  Vila. 
Table  of.  354 

— for  Running  Fits,  Table  of,  358 

— ^for  Standard  Holes,  Table  of,  858 
Tool  and  Operation  Sheet.  324 
To(d  Orlb^  Equipment  for.  120 
Todl  BngtaawrlDf,  Importance  of,  815 
Tool  Equipment,  5 

— Standard,  for  the  Shop,  110 
To«l  ikoldera,  25 
Ti«l  Layont,  322 

— Sheet,  328 
Tooboakert*  Adlnstabla  Boring  Tool. 
48 

— Tool  Equipment  of,  111 
Tooll.  Boring,  46 
—treadling.  01 
— Cutting-Off.  84 
— Fozmiag,  68 


~~ioT  Pattern  Making,  410 
—-Grinding,  24 

Ifand  and  Forged,  Clasiffioatimi 
of.  7 
— listhe,  28 

— Perishable,  Definition  of,  5 

— Permanent,  Definition  of,  5 

-splatter.  81,  87 

— -Recessing.  50 

— Threading,  65 
TtaMUlaaton-Caaa  Ooioi^  8«t-0n  Jig 
for,  266 

--Trunnion  Jig  for,  284 
Tttnimtng  Dia,  Example  of,  on  Rough 

Forging,  30 
Trunnion  Jig,  284 

Tnnlaf  and  Boring  Attachment,  Ec- 
centric, for  Packing  Rings,  200 
Taming-Tool  Head,  Multiple,  68 
Sttnlng  Tools,  57 
—Adjustable,     witb  Roller-Baek 

Rests.  59 
— for  Vertical  Boring  Mills,  62 
— Open-Side,  60 
— Overhead,  60 

— Piloted,  for  Rapid  Production,  61 
Tnirat-Latba  Attaehmant  for  Oenatmt- 

ing  Bevel  Pinions,  211 
Tnrrat  Lathe,  Box  Tool  for,  58 
— ^Bnllard  Vertical.  Cuttlng-Lubri- 

cant  System  for,  299 
— ^Forming  Tool  for,  57 
— Horisontal,  Internal  Lubrication 

of  for  Drilling,  296 
— ^Lubrication  of.  through  Spindle, 

296 

— Machine-Tool  Record  Card  tor, 
321 

—Recessing  Tools  for,  52 

— Vartical,  Angular  Generating  At- 

tachment  for,  216 
— ^Vertical.    Radius-Generating  At- 
tachment for,  214 
Tvlat  Drills,  37 

— ^Flat,  38 
Tipo-Jawad  Olmeka,  127 
T«a-Idp  Slottliif  Outtata,  78 

HUvmal  Joint,  Grinding  Fixture  for, 
841.  246 

Valve  Stem,  Receiver  Ganga  far.  871 
V-Blocks,  116 

—Principle  of.  170 
¥«ttleal  Boring  Mill,  Expanding  AllMr 
and  Face-Plate  for,  288 

—Fixtures  for,  220 


Fiztare  for  »  Fragil*  Ahuninom 
Casting,  238 
—Threaded  Knock-OfT  Arbor  Ittt,  ttS 
— Turning  Tools  for,  62 
Ytctlcal  Tnzxvt  Lathe,  Angular  Gen- 
orating  Attadunent  fnr,  116 
•— Catting-Lnbricant  System  for,  299 
— Badiaa-0«ii«Tatinf  Attaduaeat  iwt, 
SU 


ViaM»  Bench.  117 
-—Hand,  114 

— Machine  ant  HaanflMtafing^  IS4 
— Hpe,  117 


Wazpaga  of  Patterns,  423 
Wom-Oear  Hob  MiUing  Cutter,  88 
WtnMtaV'  SmIm^  ^Ifartaw  for,  176 


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